Optical disc player for playing a disc in a selected format

ABSTRACT

A system for playing a selected one of multiple audio tracks recorded in synchronized fashion with a motion picture on an optical disk. The optical disk has encoded on it a mixing master music and effects (“M&amp;E”) track, or a switching master M&amp;E track. Individual audio tracks are provided for language-specific versions of the same motion picture, but these tracks have data recorded in them only where there is dialog. In this way, for many a motion picture, all tracks but masters will have data recorded for well less than half of the running time of the motion picture. When a mixing master is used, it is mixed with a language-specific track when the latter has dialog; the mixing master contains no dialog. If a switching master is used, it may contain dialog recorded with the M&amp;E; when a language-specific track has dialog recorded in it, it also contains M&amp;E and the track is played to the exclusion of the switching master.

[0001] This invention relates to the generation of audio signals duringplay of a software (e.g., motion picture) carrier, and more particularlyto a technique by which multiple dialog languages may be recorded onseparate audio tracks of the same carrier without requiring a full trackfor each language version.

BACKGROUND OF THE INVENTION

[0002] The most widespread medium for distributing motion pictures isthe videocassette. The conventional practice is to provide only onelanguage soundtrack on each videocassette. This means that differentversions of the same motion picture must be prepared for distribution indifferent countries. Rather than to dedicate a different version of thesame motion picture to each of several different languages, it would befar more advantageous to provide all desired sound tracks, containingdifferent dialog languages, on the same carrier; this would require theproduction of far fewer versions of the same motion picture. Because ofthe large storage requirements, however, this has not proven to bepractical. In fact, the only practical consumer use of multiple soundtracks on the same carrier is the provision of annotated andnon-annotated soundtracks in some laserdisc releases. (It is possible,for example, to store different soundtracks in the digital and analogaudio channels of a laserdisc.)

[0003] Despite the fact that it has occurred to others in the prior artto provide multiple soundtracks on the same software carrier, certainlythe provision of perhaps a dozen different soundtracks, in differentdialog languages, all on the same consumer software carrier, is not tobe found anywhere. Not only are there no consumer players capable ofselecting one from among so many different soundtracks, but softwarepublishers have just not found it practical to store so much audioinformation on a single carrier. The traditional approach is to publishdifferent versions of the same motion picture for distribution indifferent territories where different languages are spoken.

[0004] Digitally encoded optical disks are in theory far superior forthe distribution of motion pictures and other forms of presentation.Especially advantageous is the use of “compressed video,” by which it ispossible to digitally encode a motion picture on a disk no larger thanthe present-day audio CD. While much effort has been expended indeveloping compressed video systems, less work has been devoted to theprovision of multiple soundtracks on the same software carrier. Theconventional thinking is to pack as much video as possible on any givendisk, but still to provide a different soundtrack version carrier foreach required dialog language.

[0005] It is therefore an object of this invention to provide a systemand method for a software publisher to record on a software carrier,such as an optical disk, a motion picture accompanied with multiplesoundtracks, in different dialog languages, while at the same timeeliminating redundant information so that the storage is as efficient aspossible.

SUMMARY OF THE INVENTION

[0006] A key to the understanding of the present invention is that thereare sections of many video programs in which no dialog occurs. In theabsence of dialog, there is no reason to provide a language-specifictrack. During any “no-dialog” sequence, all that are available, if eventhat, are music and effects. Thus a music and effects (M&E) track isreally all that is necessary—for all language versions—during much ofthe total running time of a motion picture. In fact, an M&E track is allthat is required in the usual case for far more than half the runningtime. Obviously, a Shakespearean movie will have more dialog, and hencemore language-specific dialog, than an action-adventure movie.Nevertheless, most present-day releases have far more non-dialog M&Ethan they do the spoken word.

[0007] Before summarizing the invention, it is to be appreciated thatthe present invention contemplates data-efficient storage and recoveryof various audio versions, and not just different language moviesoundtracks. For example, multiple soundtracks could include teachingand testing versions of the same material, and there could perhaps beteaching and testing versions for multiple impels of expertise. Themultiple soundtracks that would be provided in such a case might evenhave some dialog in common, not only M&E. Thus, it is to be understoodthat the object of the invention is to provide a plurality of audiotracks synchronized with a motion picture, and not necessarily audiotracks which differ only in terms of language. It is also to beunderstood that the invention is not limited to a particular medium, andit is applicable to tape carriers and all digital storage media, notjust the optical disks of the illustrative embodiment of the invention.Nor is the invention limited only to the distribution of motionpictures. For example, in an extreme case, the invention is applicableto the distribution of a library of still pictures, in which case thereis no “motion” at all. The term “audio tracks” thus embraces much morethan audio tracks with different dialog languages, the term “softwarepublisher” thus embraces much more than a motion picture company, andthe term “carrier” embraces much more than a digitally encoded opticaldisk.

[0008] The illustrative embodiment of the invention is an optical diskwhich includes multiple audio tracks synchronized with a motion picturetrack. At least one of the audio tracks is a mixing master or aswitching master. A mixing master is a track which includes M&E, but forthe most part no dialog. A switching master is a track which includesM&E, together with dialog in a particular language. Other tracks on thedisks are specific to respective languages and include material that islanguage specific. Where no language-specific material is required for aparticular audio track, nothing is recorded so that there is no wasted“real estate,” as will be described below. Consider the case of a mixingmaster M&E track, and three language-specific audio tracks in English,Spanish and French. For a two-hour movie, the M&E track might haverecorded close to two hours of audio. (Where there is no sound at all,there is no need to store any data, once again in order to avoid wastingany storage capacity.) The three language-specific tracks have dialogrecorded in them, but no music and no effects—and each of the threetracks has data recorded in it only where it is necessary for dialog.The user selects one of tile three tracks, the French track, forexample, if he wants to hear the French version of the movie. The mixingmaster audio track and the French audio track are the only ones whichare read by the player, and the digital information recorded in the twotracks is mixed, so that the net result is a conventional soundtrack, inFrench. To play the Spanish version of the same movie, the user wouldsimply select the Spanish-soundtrack instead of the French.

[0009] A switching master, on the other hand, would typically includedialog. Consider a motion picture which is originally shot with theactors speaking English. The switching master audio track would includethe original motion picture soundtrack. To play the English version ofthe release, the switching master audio track would be played by itselffrom beginning to end. But suppose that it is desired to play the Frenchversion of the motion picture. In this case, the French audio trackwould include not only French dialog, but French dialog together withmusic and effects. All that is necessary to derive the French version ofthe motion picture is to play the switching master audio track most ofthe time, but to switch from it to the French audio track—and to playthe French audio track alone—where there is French dialog. The majordifference between using mixing and switching masters is that the formeris mixed with one of the language-specific tracks so that M&E can be(although does not necessarily have to be) recorded only on the mastertrack, while in a switching system only one track is played at any giventime so that M&E has to be recorded on the language-specific tracks. Itis also possible to provide both schemes on the same disk, i.e., toprovide both kinds of master tracks, with some of the language-specifictracks being used with the mixing master, and some being used with theswitching master.

[0010] The disk includes within its lead-in section a series of codeswhich identify whether each audio track on the disk is a mixing master,a switching master, a track to be mixed with a mixing master, or a trackto be switched with a switching master. There are a maximum of 16 audiotracks which may be provided. However, there are many more languagesthan this number. It is necessary to identify which languages areavailable on the disk so that the user can control his player togenerate a soundtrack in the desired language. For this reason, thelead-in section of the disk identifies which languages are available onthe disk. In the illustrative embodiment of the invention, the firstaudio track is an M&E track, a mixing master or a switching master. Ifthere are a total of N audio tracks, where N is 16 or less, then theremay be N−1 language-specific audio tracks. (There would be N−2language-specific tracks if both mixing and switching masters areprovided.) If the first track is a mixing master, then there can be atmost N−1 language-specific versions since dialog is available onlystarting with the second track. (Theoretically, if the first track is aswitching master and it contains dialog in the original language, thenthis track can be played alone from beginning to end and there are Nlanguage versions available.) If a player determines from an analysis ofthe lead-in section of the disk that the first audio track is a mixingmaster and the fourth audio track contains dialog in French, and it thisfourth track that is to be mixed with the mixing master, then all thatis required for generation of a French soundtrack is to mix the firstand fourth soundtracks. This is not to say that there will always bedata in these tracks. On the contrary, the underlying assumption of theinvention is that the French-specific audio track will, more often thannot, contain no data.

[0011] Information recorded on the software carrier is recorded inseparately identifiable blocks. This is true for both video and all ofthe synchronized audio. Each block contains indicia of which audiotracks in the block represent a signal. Thus, a particular block maycontain switching master information, as well as information in alanguage-specific track which is to be switched with the switchingmaster. When the player determines at the start of the reading of ablock that the block contains data in a language-specific track, itswitches from play of the switching master to play of thelanguage-specific track. All it takes is a single bit for each of the upto N tracks at the beginning of a block to allow the player to determinewhether respective language-specific information is in the block beingprocessed.

[0012] Other features of the invention will be described below. Forexample, a citizen of Spain, who purchases a player and optical disks inSpain, can be assumed to want to hear Spanish versions of a motionpicture. Therefore, a player sold in Spain should “default” to play of aSpanish audio track if one is available on the disk. Only if the defaultlanguage is not available, or the user actually wants to hear dialog ina different language, should she be required to choose from among theavailable languages. How the data is stored on software carriers, andhow it is accessed and played, will be discussed at length below.

[0013] The invention is disclosed in the context of an overall systemwhich offers numerous advantageous features. The entire system isdescribed although the appended claims are directed to specificfeatures. The overall list of features which are of particular interestin the description below include:

[0014] Video standard and territorial lock out.

[0015] Play in multiple aspect ratios.

[0016] Play of multiple versions, e.g., PG-rated and R-rated, of thesame motion picture from the same disk, with selective automaticparental disablement of R-rated play.

[0017] Encrypted authorization codes that prevent unauthorizedpublishers from producing playable disks.

[0018] Provision of multiple-language audio tracks and multiple-languagesubtitle tracks on a single disk, with the user specifying the languageof choice.

[0019] Provision of multiple “other” audio tracks, e.g., each containingsome component of orchestral music, with the user choosing the desiredmix.

[0020] Variable rate encoding of data blocks, and efficient use of bitcapacity with track switching and/or mixing, to allow all of the abovecapabilities on a single carrier.

[0021] Further objects, features and advantages of the invention willbecome apparent upon consideration of the following detailed descriptionin conjunction with the drawing, in which:

[0022]FIG. 1 depicts a prior art system and typifies the lack offlexibility in, and the poor performance of, presently available mediaplayers;

[0023]FIG. 2 depicts the illustrative embodiment of the invention;

[0024]FIG. 3 is a chart which lists the fields in the lead-in portion ofthe digital data track of an optical disk that can be played in thesystem of FIG. 2;

[0025]FIG. 4 is a similar chart which lists the fields in each of thedata blocks which follow the lead-in track section of FIG. 3;

[0026] FIGS. 5A-5E comprise a flowchart that illustrates the processingby the system of FIG. 2 of the data contained in the lead-in tracksection of an optical disk being played;

[0027]FIG. 6 is a flowchart that illustrates the processing of the datablocks, in the format depicted in FIG. 4, that follow the lead-insection of the track;

[0028]FIG. 7A is a state diagram and legend that characterize the mannerin which the player of the invention reads only those data blocks on adisk track that are required for the play of a selected version of amotion picture or other video presentation, and FIG. 7B depicts the wayin which one of two alternate versions can be played by following therules illustrated by the state diagram of FIG. 7A;

[0029]FIG. 8 depicts symbolically a prior art technique used incompressing the digital representation of a video signal; and

[0030]FIG. 9 illustrates the relationships among three different imageaspect ratios.

THE PRIOR ART

[0031] The limitations of the prior art are exemplified by the system ofFIG. 1. Such a system is presently available for playing a single sourceof program material, usually a VHS videocassette, to generate a videosignal conforming to a selected one of multiple standards. A system ofthis type is referred to as a multi-standard VCR, although stand-alonecomponents are shown in the drawing. Typically, a VHS tape 7 hasrecorded on it an NTSC (analog) video signal, and the tape is played ina VHS player 5. The analog signal is converted to digital form in AIDconverter 9, and the digital representations of successive frames arewritten into video frame store 11. Circuit 13 then deletes excessframes, or estimates and adds additional frames, necessary to conform tothe selected standard, e.g., PAL. To convert from one standard toanother, it is generally necessary to change the number of horizontallines in a field or frame (image scaling). This is usually accomplishedby dropping some lines, and/or repeating some or averaging successivelines to derive new line to be inserted between them. The main functionof circuit 13, of course, is to convert a digital frame representationto analog form as the video output

[0032] Systems of the type shown in FIG. 1 generally degrade the videooutput. Conventional videocassettes deliver reduced quality video whenthey support more than one video standard. One reason is that there is adouble conversion from analog to digital, and then back again. Anotheris that the image scaling is usually performed in a crude manner(deleting lines, repeating lines and averaging lines). There are knownways, however, to perform image scaling in the digital domain withoutdegrading the picture. While not generally used, the technique is in theprior art and will therefore be described briefly as it is also used inthe illustrative embodiment of the invention.

[0033] To give a concrete example, the PAL standard has 625 lines perframe, while the NTSC standard has 525 lines per frame. Because no partof the image is formed during the vertical retrace, not all of thehorizontal line scans in either system are usable for representing imageinformation. In the PAL standard there are nominally 576 lines per framewith image information, and in an NTSC frame there are nominally 483lines with image information.

[0034] To convert from one standard to another, successive fields arefirst de-interlaced. Then 576 lines are converted to 483, or vice versa,and re-interlaced. How this is done is easy to visualize conceptually.Consider, for example, a very thin vertical slice through a PAL frame.The slice is broken down into its three color components. Image scalingfor converting from PAL to NTSC, from a conceptual standpoint, isnothing more than drawing a curve based on 576 PAL pieces of color dataand then dividing the curve into 483 parts to derive a piece of data foreach horizontal line of the desired NTSC signal. In actuality, this isaccomplished by a process of interpolation, and it is done digitally.(Image scaling, in general, may also involve a change in the aspectratio, for example, in going from HDTV to NTSC, and may require clippingoff information at both ends of every horizontal line.)

[0035] While prior art systems thus do provide for standards conversion,that is about the extent of their flexibility. The system of FIG. 2, onthe other hand, offers unprecedented flexibility in ways not evencontemplated in the prior art.

[0036] The Illustrative System of the Invention

[0037] The system of FIG. 2 includes a disk drive 21 for playing anoptical disk 23. Digital data stored on the disk appears on the DATA OUTconductor 25. The disk drive operation is governed by microprocessordisk drive controller 27. The read head is positioned by commands issuedover HEAD POSITION CONTROL lead 29, and the speed of the disk rotationis governed by commands issued over RATE CONTROL conductor 31. Opticaldisks are usually driven at either constant linear velocity or constantangular velocity. (Another possibility involves the use of a discretenumber of constant angular velocities.) Disks of the invention may bedriven at constant linear velocity so that the linear length of tracktaken by each bit is the same whether a bit is recorded in an inner orouter portion of the track. This allows for the storage of the mostdata. A constant linear velocity requires that the rate of rotation ofthe disk decrease when outer tracks are being read. This type of opticaldisk control is conventional. For example, the CD audio standard alsorequires disks which are rotated at a constant linear rate.

[0038] Microprocessor 41 is the master controller of the system. Assuch, it issues commands to the disk drive controller over conductor 43and it determines the status of the disk drive controller over conductor45. The disk drive controller is provided with two other inputs. Blocknumber/pointer analyzer 47 issues commands to the disk drive controllerover conductor 49, and BUFFER FULL conductor 51 extends a control signalfrom OR gate 54 to the disk drive controller. These two inputs will bedescribed below. (In general, although reference is made to individualconductors, it is to be understood that in context some of theseconductors are in reality cables for extending bits in parallel. Forexample, while the output of OR gate 54 can be extended to the diskdrive controller over a single conductor 51, block number/pointeranalyzer 47 could be connected to the disk drive controller over a cable49 so that multi-bit data can be sent in parallel rather than serially.)

[0039] An important feature of the system of FIG. 2 is that bitinformation is stored on the disk at a rate which varies according tothe complexity of the encoded material. By this is meant not that thenumber of bits per second which actually appear on the DATA OUTconductor 25 varies, but rather that the number of bits which are usedper second varies. Video information is stored in compressed digitalform. FIG. 8 shows the manner in which video frames are coded accordingto the MPEG1 and MPEG2 standards. An independent I-frame is coded in itsentirety. Predicted or P-frames are frames which are predicted basedupon preceding independent frames, and the digital information that isactually required for a P frame simply represents the difference betweenthe actual frame and its prediction. Bidirectionally predicted B-framesare frames which are predicted from I and/or P frames, with theinformation required for such a frame once again representing thedifference between the actual and predicted forms. (As can beappreciated, fast forward and fast reverse functions, if desired, arebest implemented using I-frames.) The number of bits required torepresent any frame depends not only on its type, but also on the actualvisual information which is to be represented. Obviously, it requiresfar fewer bits to represent a blue sky than it does to represent a fieldof flowers. The MPEG standards are designed to allow picture frames tobe encoded with a minimal number of bits. Frame information is requiredat a constant rate. For example, if a motion picture film is representedin digital form on the disk, 24 frames will be represented for eachsecond of play. The number of bits required for a frame differsradically from frame to frame. Since frames are processed at a constantrate, it is apparent that the number of bits which are processed (used)per second can vary from very low values to very high values. Thus whenbits are actually read from the disk, while they may be read from thedisk at a constant rate, they are not necessarily processed at aconstant rate.

[0040] Similar considerations apply to any audio stored on the disk. Anydata block may contain the bit information required for a variablenumber of image frames. Any data block may similarly contain the bitinformation required for a variable time duration of a variable numberof even numerous audio tracks. (There is just one physical track. Thereference to multiple audio tracks is to different series oftime-division slices containing respective audio materials.) The audiotracks contain digital information, which may also be in compressedform. This means that if there is information stored in any data blockfor a particular audio track, those bits do not necessarily representthe same time duration. It might be thought that the duration of thesound recorded for any audio track corresponding to any picture framesrepresented in a block would be the duration of the picture frames.However, that is not necessarily true. This means that audio informationmay be read before it is actually needed, with the reading of more audioinformation pausing when a sufficient amount has already accumulated orwith audio not being included in some data blocks to compensate for thepreceding over-supply. This leads to the concept of buffering, thefunction of audio buffers 53, video buffer 55, pan scan buffer 57,subtitle buffer 59, and OR gate 54 which generates the BUFFER FULLsignal.

[0041] As each data block is read from the disk, it passes through gate61, provided the gate is open, and the bit fields are distributed bydemultiplexer 63 to the various buffers and, over the COMMAND/DATA line65, to master controller 41. Each data block in the illustrativeembodiment of the invention contains video bit information correspondingto a variable number of picture frames. As discussed above, there may bea large number of bits, or a small number, or even no bits (for example,if the particular disk being played does not represent any video).Successive groups of video data are stored in video buffer 55 separatedby markers. Video decoder 67 issues a command over conductor 69 when itwants to be furnished with a new batch of data over conductor 71.Commands are issued at a steady rate, although the number of bitsfurnished in reply vary in accordance with the number of bits requiredfor the particular frames being processed. The rate at which bits areread from the disk drive is high enough to accommodate frames whichrequire maximal information, but most frames do not This means that therate at which data blocks are actually read is higher than the rate atwhich they are used This does not mean, however, that a well-designedsystem should delay reading of a block of data until the data isactually required for processing. For one thing, when data is actuallyrequired, the read head may not be positioned at the start of thedesired data block It is for this reason that buffering is provided. Thevideo buffer 55 contains the bit information for a number of successiveframes (the actual number depending upon the rate at which bits areread, the rate at which frames are processed, etc., as is known in theart), and video data block information is read out of the video bufferat a constant frame rate determined by video decoder 67. Video data isdelivered to the buffer only until the buffer is full. Once the bufferis full, no more information should be delivered because it cannot bestored. When the video buffer is full, a signal on conductor 69 causesthe output of OR gate 54 to go high to inform disk drive controller 27that one of the buffers is full.

[0042] Similar remarks apply to the three other types of buffers. (Thereis a single subtitle buffer 59, a single pan scan buffer 57, andnumerous audio buffers 53, the purpose of all of which will be describedbelow.) When any of these buffers is full, its corresponding outputcauses OR gate 54 to control the BUFFER FULL conductor to go high and toso inform the disk drive controller that one of the buffers is full.Audio buffers 53 and subtitle buffer 59 operate in a manner comparableto that described for video buffer 55. Audio processor decoder 71 issuesa command to the audio buffers when it requires audio track data, atwhich time the audio buffers furnish such data. Similarly, graphicsgenerator 73 retrieves data from subtitle buffer 59, and pan scanprocessor/vertical scaler 87 receives data from pan scan buffer 57 aswill be described below.

[0043] When any one of the four buffers is full (which includes any (oneof the individual buffers within the block 53), the disk drivecontroller 27 causes the disk drive to stop reading data. Data is notread again until all of the buffers can accept it, i.e., until no bufferis full and conductor 51 goes low. (Conversely, if the buffers are beingdepleted of data too rapidly, an adjustment in the RATE CONTROL signalon conductor 31 increases the disk speed and thus the rate at which thebuffers are filled.)

[0044] This discussion of buffering arose from a consideration of theBUFFER FULL input 51 to the disk drive controller 27. The other inputwhich remains to be described is that represented by cable 49. As willbe described below, every data block has a serial block number as wellas pointer information at its beginning. Circuit 47 reads the serialblock number and analyzes the pointer information. The pointer, a serialblock number, points to the next data block which should be read. Thisinformation is furnished to the disk drive controller over cable 49. Itis in this way that the disk drive controller can control positioning ofthe read head of the disk drive so that the desired data block can beaccessed. Many times the wrong block will be read—this is to be expectedin the case of a jump to a new block, as is the case, for example, whena jump is made from one track to another when playing a CD audio disk.If the disk drive reads a data block whose serial block number is toohigh or too low, this is determined by block number/pointer analyzer 47which then issues a new command over cable 49 to the disk drivecontroller to cause it to read another block with a lower or higherserial block number respectively. During the time that the read head ispositioning itself to read a new block, the data which is read is notactually used. Gate 61 remains closed so that the information is notdelivered to the demultiplexer 63 for distribution to the four buffersand to the master controller 41 over the COMMAND/DATA lead. It is onlywhen the correct data block is reached, as determined by circuit 47analyzing the serial block number at the start of the block, thatconductor 75 is pulsed high to open gate 61.

[0045] The remainder of the block is then delivered to thedemultiplexer. The data bits read from the disk are also delivered tothe microprocessor master controller 41 over conductor 77. Each datablock contains not only bit information which must be distributed to thevarious buffers, but also control information, e.g., bits that identifythe kind of data actually to be found in the block The identificationbits (flags and the like, as will be described below) are furnished tothe master controller so that it is in control of the system at alltimes. The identification bits are used by the demultiplexer to controldata distribution to the various buffers. (The master controller issuescommands over conductor 76 to the block number/pointer analyzer 47 whichexercise not only general control over this element, but also specificcontrol by causing element 47 to turn off the enabling signal onconductor 75 as is appropriate to prevent full data blocks from enteringthe demultiplexer if they are not required for subsequent processing.)

[0046] The master controller is at the heart of the system and in factcarries out the bulk of the processing to be described below. The userof the player communicates with the master controller via an interface79, typically a keyboard. The user also is provided with a key and lockmechanism, shown symbolically by the numeral 81, which is referred toherein as the “parental lock” option. If the lock is turned on, thenR-rated motion pictures will not play. The manner in which this iscontrolled by bits actually represented on the disk will be describedbelow. If the lock is on, and only an R-rated picture is on the disk, adisabling signal on PARENTAL LOCK CONTROL conductor 83 closes gate 61.No data bits are transmitted through the gate and the disk cannot beplayed. As will become apparent below, if the disk also has on it aversion of the film which is not R-rated, it will play if it is selectedby the viewer. Although the parental lock feature is shown as requiringthe use of an actual key and lock, it is to be understood that thefeature can be implemented by requiring keyboard entries known only to achild's parents. The manner of informing the master controller thatR-rated versions of a motion picture should not be viewed is notrestricted to any one form. Just as physical keys and coded keys arealternatively used to control access to a computer, so they can be inthe system of FIG. 2. What is important is the way in which twodifferent versions can be represented on the same disk (withoutrequiring the full version of each), and how the system determineswhether a selected version may be played in the first place. This willbe described below.

[0047] Master controller 41 includes several other outputs which havenot been described thus far. Conductor 85 represents a MASTER CLOCK buswhich is extended to all of the sub-systems shown in FIG. 2. In anydigital system, a master clock signal is required to control the properphasing of the various circuits. The six other outputs of the mastercontroller are extended to demultiplexer 63, audio processor decoder 71,pan scan processor/vertical scaler 87, video frame store, interlace and3:2 pulldown circuit 89, graphics generator 73, and sync generator andDVA converter 92. These are control leads for governing the operationsof the individual circuit blocks.

[0048] Audio processor decoder 71 processes the data in buffers 53 andderives individual audio analog signals which are extended to anamplifier/speaker system shown symbolically by the numeral 91. Videodecoder 67 derives a DIGITAL VIDEO signal on conductor 93 from thecompressed video data which is read from buffer 55. The digital video isfed to pan scan processor/vertical scaler 87 frame by frame. Theparticular video coding/decoding that is employed is not a feature ofthe present invention. A preferred standard would be one along the linesof MPEG1 and MPEG2, but these are only illustrative. The same is true ofthe audio track coding. The present invention is not limited toparticular coding methods.

[0049] The operations of circuits 57 and 87 can be best understood byfirst considering the symbolic drawing of FIG. 9. The digitalinformation which is stored on the optical disk in the preferredembodiment of the invention characterizes frames having a “master”aspect ratio of 16:9, the so-called “wide screen” image. The masteraspect ratio is shown on the upper left in FIG. 9. If the ultimateanalog signal to be displayed on the user's television receiver requiresthis aspect ratio, and the number of horizontal scan lines with pictureinformation (as opposed to horizontal scan lines which occur duringvertical retrace) corresponds with the number of horizontal linesrepresented by the video bit information stored on the disk, then thegeneration of the video analog signal is straightforward. But if thetelevision receiver of the user accommodates a TV signal having a 4:3aspect ratio, and the master aspect ratio on the disk is 16:9 ratherthan 4:3, then there are two choices. One is to display the originalpicture in “letter box” form. As depicted on the right side of FIG. 9,what is done in this case is to vertically compress uniformly a masterimage so that its horizontal dimension fits into the confines of thetelevision receiver. This results in the vertical dimension beingshortened at the same time so that it fills less than the full height ofthe TV display area. What this means is that the horizontal line scansat the top and bottom of each overall frame must be blanked, with darkbands forming in their place—but the original aspect ratio is preserved.The other option is for a “pan scan” reduced aspect ratio. What thisinvolves is superimposing a box having a 4:3 aspect ratio on theoriginal wide screen image. As a result, the left side of the picture,the right side, or both sides, are clipped off. (In all cases, even if awide screen image corresponding to a 16:9 master aspect ratio is to beshown, it may be necessary to form a number of horizontal line scanswhich is different from the number of horizontal lines represented onthe disk. The number of horizontal lines is a function of the videosignal standard to which the video output must conform. Changing thenumber of lines is a process known as vertical scaling, as describedabove.)

[0050] With respect to pan scan processing, it will be apparent fromFIG. 9 that in order to identify that portion of a 16:9 master aspectratio picture which should be used to form a pan scan reduced aspectratio picture, all that is required is to specify the starting pointalong each horizontal line scan of the information that should be used.Specifying a single number (e.g., column 200 out of a total of 960columns) suffices for this purpose. The issue, however, is whether thesame column is always used. In some cases the player may be told that ifa 4:3 aspect ratio is desired, it should always be taken from the middleof the wide screen image. In other cases, a variable column startingpoint may be desired, in which case a data block actually containsinformation which represents the starting column number which should beused from that point until another change is effected.

[0051] As will become apparent below, the video information in each datablock includes a flag which represents whether the pan scan columninformation should be updated. If there is such a flag, video decoder 67issues a command over conductor 95 to pan scan buffer 57. At this timethe buffer accepts a pan scan update from demultiplexer 63. That updateremains in the buffer, for use by pan scan processor/vertical scaler 87with the succeeding frames, until another change takes place.

[0052] It is in pan scan processor/vertical scaler 87 that the number ofhorizontal lines is adjusted and the aspect ratio is changed. Thedigital video is furnished by video decoder 67 and the pan scaninformation, if it is required, is provided by buffer 57. The output ofcircuit 87 consists of uncompressed digital video, in the desired aspectratio and represented by the number of horizontal lines required for theselected television standard.

[0053] Once video frame information is stored digitally in frame store89, it can be broken up into interlaced fields if the selected standardrequires it. Also, 3:2 pulldown is the technique used to convert24-frames-per-second motion pictures to 60-fields-per-second video (thenominal values of 24 and 60 are in reality 23.97 and 59.94); to convertdata representative of a motion picture to an NTSC format, frameinformation (data blocks) must be read at the rate of 24 per second. (Asis standard in the art, such a transformation applies frame 1 of thesource material to fields 1, 2 and 3 of the video signal, frame 2 of thesource material to fields 4 and 5 of the video signal, frame 3 of thesource material to fields 6, 7 and 8, etc., thus yielding 60 fields for24 original frames.) On the other hand, conversion to the PAL standardis relatively simple, and 3:2 pulldown is not required. The PAL standardrequires 50 fields per second. Frames are processed at the rate of 25per second, and every frame is used to form two fields. (Because motionpicture films are shot at the rate of 24 frames per second yet processedat the rate of 25 per second when converting to PAL, everything whichoccurs on the TV screen takes place 4% faster in Europe than it does inthe United States.) Whether the frames are processed at the rate of 25per second or 24 per second is controlled by changing the frequency ofthe MASTER CLOCK signal on bus 85.

[0054] The output of block 89 is digital, and is extended to syncgenerator and D/A converter 92. It is in this element that appropriatesync pulses are inserted into the fields, and the digital information isconverted to analog. Any subtitles that are required are contained inbuffer 59. Under control of microprocessor 41, commands are issued overcontrol lead 97 to graphics generator 73. This conventional circuitretrieves coded character information from the subtitle buffer, andgenerates a VIDEO signal on conductor 99 which depicts the subtitles.The KEY signal is generated on conductor 98, and the two signals areextended to a conventional keyer circuit 96. This device merges thesubtitles with the video image (utilizing hard or linear keying at themanufacturer's option, as is known in the art), and extends thecomposite video signal to a conventional TV display device 94.

[0055] Lead-In Track Fields

[0056] Before proceeding with a description of the detailed processing,it will be helpful to consider the information which is stored in thelead-in portion of the disk track. This information is stored inindividual fields as depicted in FIG. 3, and it is this informationwhich controls subsequent processing of the data read from the disk. Theformat of a data block is shown in FIG. 4, but for an understanding ofhow the data in this block is used, it is necessary to appreciate theset-up information which is read first.

[0057] Referring to FIG. 3, at the start of the track there are a numberof lead-in sync bits. Although for all other entries minimum and maximumnumbers of bits are depicted in the appropriate columns, no such numbersare provided for the lead-in sync bits. The number of sync bits requiredat the beginning of the track depends on the hardware employed. Giventhe particular hardware and range of disk speeds involved, a sufficientnumber of sync bits are provided at the start of the track to allow thecircuits involved with reading the disk, including disk drive controller27 and block number/pointer analyzer 47, to synchronize themselves tothe bit stream on DATA OUT conductor 25. Bit synchronization is atechnique well known in digital systems.

[0058] The second field consists of 40 bits representing authorizedterritories. There are several ways in which software publishers canlock out play of their software. The most important involve controllingwhether R-rated motion pictures can be played (the parental lock outoption), and whether the final analog output video signal can assume thestandard selected by the user. It is in this way, for example, that asoftware publisher might allow a motion picture to be played on an NTSCreceiver but not a PAL receiver. But as long as the player is providedwith this kind of lock out control, it can be extended to territories.All players used with the disks of the invention conform to the same setof specifications. One feature of the design is that each player isprovided with a representation of the territory or territories for whichit has been intended for sale. For example, the territory or territoriescan be represented by the settings of a DIP switch, a code stored in amicroprocessor ROM (e.g., in master controller 41) or the like. It isassumed that there are a total of 40 possible territories. Each disk hasa 40-bit field in its lead-in section, each bit of which is associatedwith one of the 40 territories. A 1 in any bit position is an indicationthat the disk is authorized for play in the respective territory, and a0 is an indication that it is not. A player whose code indicates that itis for sale in China, for example, will not play a disk if there is a 0in the 40-bit territory field at the position associated with China.

[0059] As an example of the use of such a feature, consider a playerintended for sale in a particular country. A software publisher mightput out a motion picture film which for contractual reasons is not to bereleased in that country. It is for this reason that a 0 would be storedin the bit position associated with that country in the authorizedterritories field of the lead-in section of the track. Upon sensing thisbit, master controller 41 would cause circuit 47 to generate an inhibitsignal on conductor 75 which would permanently cause gate 61 to blockall data from passing through it.

[0060] The third field is a single bit, a flag which indicates whetherthere is any information in the following field. This information istermed herein “special software.” The player of FIG. 2 ordinarilyexecutes the same software code, typically contained in read-onlymemory. It is this code which will be described in connection with theflowcharts of the drawing. However, since the player is microprocessorcontrolled, there is no reason why it cannot be used for some eventotally unrelated purpose, and this can be enabled simply by loadingsoftware from the disk. If the special software flag is a 1, then mastercontroller 41 reads on conductor 77 the software which immediate followsin field 4. Thus depending on whether the special software flag is a 0or a 1, the fourth field is either empty or contains software ofundetermined length. At the end of the software there is a sync wordwhich is unique in the sense that this word is not allowed to occuranywhere in the overall data stream. When the sync word pattern appears,it is an indication that the preceding data field has come to an end,and a new field follows. (In the event data having the sync word patternwould otherwise appear in the data stream and be misinterpreted as async word, it can be avoided using known techniques. For example, if thesync word consists of 32 bits of a predetermined pattern, and someoverall data sequence includes this pattern within it, then after 31bits of the data pattern are recorded, an extra bit, having a valueopposite that of the last bit in the sync word pattern, may be insertedin the bit stream. When the player sees this bit, it discards it andtreats the following bit as a data bit instead of the last bit of thesync word.)

[0061] An example of special software might be software for controllingvideo games. While the player is provided with an operating systemdesigned for the play of motion pictures and multi-track audios, it iscertainly feasible for the player to perform additional and/or differentfunctions involved in the play of video games. This is especially trueif the user interface is detachable and joysticks and the like may beconnected in place of a keyboard to accommodate game-playing peripheralequipment. The system can be converted to a video game player simply bystoring the necessary software as it is read from the disk. While in theflowcharts to be described below the special software is shown as beingself-contained and not involving the standard processing steps, thespecial software can certainly call operating system subroutines forexecution in order to take advantage of the built-in code.

[0062] The fifth field consists of 12 bit positions, each correspondingto a different standard. Standards include 1250-line European HDTV,1125-line Japanese HDTV, 1050-line proposed American HDTV (as well as1080-line and 787-line proposed standards), 625-line PAL, 525-line NTSC,625-line SECAM, 360-line “letter box”, etc. It is even possible toaccommodate future standards, although to form an appropriate videosignal in such a case different software would be required. However,that simply entails providing software on a disk to supplement thebuilt-in operating system.

[0063] As a single example, if the first bit position of the 12-bitfield corresponds to the NTSC standard, and if the user selects an NTSCstandard for play on his TV receiver, or if that is his default setting(as will be discussed below), then an NTSC signal will be generated onlyif the first bit in the authorized standards field is a 1.

[0064] Field 6 always contains 100 bits. These bits represent respectiveaudio languages—dialog—for a motion picture. It is rare that so manyforeign-language versions of the same motion picture will be prepared,and it is not contemplated that so many versions will actually beincluded on a disk. In fact, there are a maximum of 16 audio trackswhich can contain dialog in different languages. Each of the 100 bits,except the first, represents one of 99 languages. If there is a 1 in thecorresponding bit position, it is an indication that there is an audiotrack with dialog in the corresponding language.

[0065] The first of the 100 bit positions does not really correspondwith a language. Instead, a 1 in the first bit position means that thereis a music and effects (“M&E”) track. (By “effects” is meant such thingsas the sound associated with thunder, gunshots and the like.) Asindicated in the Comments field on FIG. 3, there are N “1”s in field 6of the lead-in section of the overall track, where N has a maximum valueof 16 (one M&E track and up to 15 dialog tracks, or up to 16 dialogtracks without M&E). As a single example, suppose that the third bitposition corresponds with French, the fifth corresponds with Greek, andthe 100-bit field is 10101000 . . . 0. This means that there is an M&Etrack, as well as French and Greek dialog tracks. It does not mean thatevery single data block on the disk includes bit information whichrepresents M&E, and French and Greek dialog. What it does mean is thatany data block has at most three audio tracks with M&E and/or dialog. Italso means that any data block which has such audio track informationcontains the information in the order M&E, French, Greek. Just how thesystem determines which specific data blocks contain audio informationfor those languages represented in the 100-bit field will be describedbelow in connection with the fields contained in a data block.

[0066] It should be understood that the language audio tracks do notnecessarily include just dialog. As will be described shortly, it ispossible to mix an M&E track with a French dialog track, with the resultbeing a complete audio track suitable for play in France. But it iscertainly possible that a particular audio track will include pre-mixedM&E and original dialog For example, if bit position 10 of the 100-bitfield represents English dialog and there is a 1 stored there, it meansthat there is an English language version of audio on the disk. However,it is possible that in the corresponding audio track there is not onlyEnglish dialog, but a full sound track including the M&E. At the sametime, there may be M&E in a separate track, if there is a 1 in the firstbit position of the 100-bit field. How the various tracks are processedin order to derive a complete sound track for play in any given languagedepends on subsequent information. Field 6 simply represents which audiolanguages are available, as well as whether there is a separate M&Etrack (without any dialog).

[0067] There is another piece of information which is necessary in orderfor the audio scheme to function, and that information is represented infield 7. For each of the N available audio language tracks (up to amaximum of 16), there is a 3-bit code in the seventh field. Beforedescribing the meaning of the codes, it must be understood how the codesare associated with particular tracks and languages. Suppose that field6 is 101010000100 . . . 0 which is interpreted to mean that there is anM&E track, a French track, a Greek track and an English track. From thisinformation alone, there is no way to tell whether there is even any M&Ein the French, Greek and English tracks. All that is known language-wiseis that dialog is available in only three languages. For this example,there would be 12 bits in field 7 The first three bits are associatedwith the M&E track, the second three bits are associated with the Frenchtrack, and the third and fourth 3-bit codes are associated with theGreek and English tracks respectively. The 3-bit codes are as follows:

[0068] 000—mixing master (M&E)

[0069] 001—switching master (M&E)

[0070] 010—dialog+(M&E), complete audio track

[0071] 011—track to be mixed with mixing master

[0072] 100—track to be switched with switching master

[0073] These five codes are all that are necessary to form completesound tracks in the three available languages, French, Greek andEnglish. How the tracks are combined will be described below, but whatshould be borne in mind is that the purpose of the entire arrangement isto provide sound tracks in many languages (up to 15), without requiringwhat might be a 2-hour audio recording for each. In fact if a movie istwo hours long, but the actual dialog is only 30 minutes, the goal is torecord one full track (M&E or original sound track), with only a30-minute audio recording of dialog for a particular language.

[0074] Field 8 contains N×4 bits, that is, 4 bits for each of the N “1”sin field 6. There is thus a 4-bit code in field 8 for each audiolanguage track which is available on the disk. The 4-bit code representsthe track type, and there are a maximum of sixteen possibilities.Typical track types are single-channel mono, two-channel Dolby,5.1-channel Musicam, etc. [The term 5.1-channel refers to left, right,center, left rear and right rear channels, together with a sub-wooferchannel.] The 4-bit track type codes allow the master controller todetermine the manner in which audio processor decoder 71 operates on thedata in the up-to-16 audio tracks to derive analog outputs for speakersystem 91.

[0075] Considering again field 7, there are several ways in which acomplete sound track, in a selected language, can be derived from thedisk. The operation of mixing involves mixing (adding together) twosound tracks. The operation of switching involves switching between twosound tracks, and playing only one of them at any given time. The firsttrack is always M&E, if it is available. The code for this track isalways 000 or 001. If the code is 000, it means that there is no dialogin the track and its M&E is to be mixed with the selected languagetrack. If the code 011 is associated with the French track, for example,it means that the first and third tracks should be mixed at all times.The dialog, when there is dialog, appears in the French track, andmixing it with the mixing master provides a complete French sound track.On the other hand, the first track may be a switching master. What thismeans is that music and effects are recorded in this track, with orwithout dialog. The French track in this case would be represented by a100 code. It contains M&E and dialog, but only when there is dialog. TheM&E track, the first, is played alone when there is no dialog, but thefifth track is played alone when there is. The tracks are switched, notmixed. The French track, when dialog is recorded in it, includes notonly dialog but M&E as well since this would be the only source of M&Ein a switched type operation.

[0076] The fifth possibility (010) is that a particular track happens tocontain the original sound track, M&E together with dialog in theoriginal language. If the dialog is in the selected language, the trackcan be played from beginning to end, by itself This track can also serveas a switching master (code 001) for other languages.

[0077] When it comes to mixing tracks, whatever audios are in the twospecified tracks (the mixing master and the track which is mixed withit) are simply added together at all times; whatever audio there is inthe two tracks gets played. It is only when switching between theswitching master and the track with which it is switched that one trackgets played in lieu of the other. It is true that each track may containaudio information only when the other does not (which would allowmixing), but it is conceivable that the switching master will alsoinclude dialog, i.e., if it is a recording of the original sound trackof the motion picture. That is why switching is employed—only one trackis heard from at any given moment. As will be described below, each datablock includes bits which inform the master controller which audiotracks actually contain data in that block. If a selected audio languagetrack with an original 100 track code has data in any data block, thenthe audio processor decoder 71 processes the data in that audio track tothe exclusion of any data which might be in the switching master track.

[0078] Field 9 on FIG. 3 contains six bits which are coded to representa number M. This is the number of “other” audio tracks, separate andapart from the up-to-16 audio language tracks. The usual use for thesetracks is to represent in compressed digital form, individualinstruments or mixes of instruments, with the user having the option ofcombining them. In an extreme form, there could be 63 separateinstrumental tracks, with the user being able to combine any tracks hedesires, and to set their relative levels before mixing. If one of thetracks contains the combined sound to begin with, it is possible todelete an instrument from the orchestral mix by specifying that itsinformation content should be deleted, or subtracted, from theorchestral mix. This would allow a user, for example, to play his pianoto the accompaniment of an orchestra playing a concerto from which pianoplay has been eliminated. It would also allow a user to single out aparticular instrument to facilitate practice. Precisely what the userdoes with the “other” audio tracks is determined by menu selectionswhich are made available to him. Field 8 simply identifies how many“other” audio tracks are present on the disk. (The term “other” audiotracks would appear to be rather non-descriptive, but this isn't thecase. The intent is that the term subsume any audio track usage otherthan the provision of sound tracks for motion pictures. Rather than tohave orchestral music in these “other” audio tracks, for example, it ispossible to have individual vocalists, allowing a user to studydifferent harmonizations.)

[0079] It is apparent that if there are indeed 63 “other” audio tracks,then much if not most of the disk capacity may be allocated to audiodata. But that is precisely why so many audio tracks are made available.It is certainly contemplated that some disks playable in the system ofFIG. 2 will not include video. In fact, field 19, to be described below,is a 1-bit field which informs the master controller whether there isany video data at all on the disk.

[0080] Once it is determined that there are M “other” audio tracks, thenext field specifies how each track is coded. As in the case of field 8,a 4-bit code is used for each of the “other” audio tracks. Thus thenumber of bits in field 10 can be as low as 0 (if there are no “other”audio tracks) or as high as 252 (63×4).

[0081] While the player can determine from reading fields 9 and 10 howmany “other” audio tracks there are, the user has to be told what is inthese tracks in order that he know what to do with them. There is adescription of each track, and it is in multiple languages. The firstthing that the player must be given is a list of the languages in whichthere are descriptions of the “other” audio tracks. A 100-bit field isused for this purpose. As indicated in FIG. 3, field 11 has 100 bits. A1 in any bit position is an indication that track definitions areavailable in the respective language. The correspondence between bitpositions and languages is the same in field 11 as it is in field 6. Itwill be recalled that the first bit position in field 6 corresponds toM&E, not a traditional “language”. The first bit position in field 11 isthus not used, and there can be at most 99 “1”s in field 11.

[0082] Before the track definitions are actually read and processed, theplayer must determine what menu choices to provide the user. Suppose,for example, that there are ten “other” audio tracks, each having soundsof different orchestral instruments Once the track definitions in theselected language are made available to the operating system, it candisplay a standard menu to the user. The user can then pick particulartracks to be played together, particular tracks to be deleted, theirrelative sound levels, and other “standard” choices. However, in casethe “other” audio tracks do not represent orchestral music, or they dorepresent it but in a way that requires unusual menu selections, thestandard operating system software for interfacing with the user so thatthe system can determine what is to be done with the “other” audiotracks will not suffice. To accommodate unusual situations, theoperating system must be provided with special software for the creationof the menu, as well as to control how the selected tracks aremixed/deleted following user selections. The technique used is the sameas the technique described above in connection with loading specialsoftware for changing the overall operation of the player (fields 3 and4). Field 12 is a single bit. If it is a 1, it is an indication thatthere is a field 13 which contains special mixing/deletion software. Asindicated on FIG. 3, field 13 thus has anywhere from no bits to anundetermined number which is dependent on the length of the specialsoftware to be loaded into the machine from the disk. The specialsoftware ends with a sync word so that the player will know when thenext field begins.

[0083] The next field, field 14, consists of the track definitionsthemselves. Since there are M “other” audio tracks, and there are Planguages in which they are to be defined for the user, P×M characterstrings are represented in field 14. Each string is separated from thenext by an escape character. First there are M character strings (trackdefinitions) in the first language corresponding to the first positionin field 11 which contains a 1, then there are M character strings inthe second language corresponding to the second bit position in field 11which contains a 1, etc. As will be described below, the user informsthe player in which of the available languages the menu which includesthe track definitions should be displayed. While the entire DATA OUT bitstream from the disk drive is extended to the master controller in thesystem of FIG. 2, only the character strings corresponding to theselected language are processed. They are processed and displayed inaccordance with the standard software, or the special mixing/deletionsoftware which was just read from field 12 if such software is includedon the disk. (It should be noted that it is the function ofdemultiplexer 63 to distribute to the several buffers only therespective data bits that are intended for them. It is controller 41that tells the demultiplexer what to do after the controller interpretsthe information in both the lead-in track section and the individualdata blocks.)

[0084] As described in connection with FIG. 2, provision is made for theinsertion of subtitles. The language is selected by the user as will bedescribed, but the player must be told the languages in which subtitlesare available. Another 100-bit field is used for this purpose. Asindicated in line 15 of FIG. 3, the “1”s in the field represent theindividual languages available for subtitles. As is the case with theavailable display languages, there is a maximum of 99 since the firstbit position corresponds to M&E which is not strictly speaking a“language.”

[0085] Field 16 is a 4-bit multiple version code. The player is informednot only whether there are two versions of the same video presentationon the disk, but also what the choices are with respect to them. Thefirst bit is a 0 if there is only one version on the disk, in which casethe second and fourth bits are ignored. Bit 1 has a value of 1 if thereare two versions on the disk. The second bit in the code tells theplayer whether the parental lock option is to be implemented, or whethera different criterion is to be used in selecting which version isplayed. The usual situation is where the parental lock option isimplemented, in which case the bit in the second position of the 4-bitcode is a 0. This informs the player that it should determine whetherthe parental lock option is “on.” If it is, R-rated (or, more broadly,adult-rated) versions should not be played. The bit in position 3 of thecode is an indication whether version A (the first or only version) isR-rated or not (0=no, 1=yes), and the fourth bit In the code providesthe same information for version B if there are two versions; if thereis only one version, the fourth bit is ignored. This is all theinformation the player needs to determine whether either or both of twoversions can be played. When there are two versions of the same motionpicture on the disk, the user is asked to select one of them. But if theparental lock option is “on” and one of the two versions is R-rated, theuser is given only the choice of playing the non-adult version, orplaying neither, as will be described below. If both versions areR-rated and the parental lock option is “on”, then the user can watchneither version.

[0086] On the other hand, it is possible that there will be two versionsof the same material on the disk, but it is not a question of one ofthem being adult-rated and the other not. For example, one version mightbe a teaching film including questions and answers, and the other mightinvolve a test on the same subject matter including just questions. Forthe most part the two versions would be the same. In such a case, thefirst bit in field 16 would still be a 1 to indicate that two versionsare available, but the second bit would now be a 1 instead of a 0, toindicate that the choice between the two versions does not depend onwhether they are R-rated or not. A 1 in the second bit position is anindication that the third and fourth bits characterize the two versionsrespectively with respect to a characteristic other than rating.

[0087] What the third and fourth bits actually mean in this case, andwhat menu choices are provided the user, has to be determined byresorting to different criteria. The same technique that was used twicepreviously is now used once again—special software is provided alongwith the version codes. Field 17 consists of a single bit which servesas a flag to indicate whether special version software is available. Ifthe bit is a 1, then field 18 is read to access the software. As in thecase of the two earlier software fields, field 18 terminates with a syncword to indicate the start of the next field. The special softwarecontrols a menu presentation that is unique for the particular disk.

[0088] The next field consists of a single bit. As indicated in FIG. 3.it informs the player whether video data is available. If it isn't, itsimply means that there are no video data block fields in the overalldata blocks to be described in connection with FIG. 4.

[0089] Field 20 is a single bit, and it identifies the base or masteraspect ratio. If the bit has a value of 0, it is an indication that anyvideo on the disk has a 16:9 “wide screen” aspect ratio, as depicted inFIG. 9. On the other hand, if the bit is a 1, it is an indication thatthe aspect ratio of the video on the disk is 4:3.

[0090] As described above, if the original video has a “wide screen”aspect ratio, then there are two ways in which a 4:3 reduced aspectratio can be derived. One way is to form the video image from the middlepart of the “wide screen” original. Another way is to “pan scan” in thesense that the section of the original image which is actually utilizedis not necessarily always the middle part. In fact, FIG. 9 shows the useof more information on the left than on the right of the original image.Field 21 is a single bit which is indicative of pan scan availability.If field 20 is a 1, the base aspect ratio is 4:3 so that pan scanavailability is irrelevant—the single bit in field 21 is simply ignored.But if the base aspect ratio is 16:9 (field 20 has a 0), the value ofthe bit in field 21 tells the player whether the subsequent data blocksprovide starting column information which can be loaded into pan scanbuffer 57 on FIG. 2. If the bit in field 21 is a 0, the data blocks donot include column number information, and if the video is to be playedin a 4:3 aspect ratio from a “wide screen” original, then the videoimage is formed from the middle part of each original frame. On theother hand, if pan scan information is available in the data blocks,then buffer 57 on FIG. 2 is updated as required and the final videoformed will have an added degree of variability.

[0091] Field 22 is a 20-bit number which represents the total number ofdata blocks on the disk. However, if there are two different versions,while they have many data blocks in common, the remaining numbers ofblocks in the two versions may be different. For example, a scene mightbe completely omitted from one of the versions, in which case it wouldhave a smaller total number of data blocks. For this reason, if field 16indicates that there are two versions of a motion picture or othersource material on the disk, field 23 provides the total number of datablocks in version A, and field 24 provides the total number of datablocks in version B. Both fields are omitted if there is only oneversion on the disk.

[0092] Each data block may include video information for a variablenumber of frames. The system could determine the total playing time fromthe number of data blocks (either the total number if there is only asingle version, or two different numbers if there are two versions),only if the system is informed of the original frame rate and theaverage number of frames represented in each block for the disk as awhole. Two disks with the same number of data blocks will have differentrunning times if the original source material for one of them was motionpicture film whose frames were generated at the rate of 24 per secondand the other had an original source material derived from a 30frame-per-second video camera. Field 25 is a 4-bit value that identifiesthe original frame rate (24, 30, etc.), a number necessary for propergeneration of the video signal. Although the time represented by eachdata block could be determined from the frame rate if each data blockcontains only one frame, it is possible to store more or less than oneframe of data in each data block. Also, there may be no frameinformation at all, i.e., the video availability flag in field 19 may be0. Consequently, field 26 is provided. This field contains a 10-bitnumber which represents the block time factor, i.e., the average timeduration represented by each block. Multiplication of the block timefactor by the total number of blocks (or the total number in aparticular version) yields the running time. (In practice, the blocktime factor is about the same for both versions on a disk. If desired,individual block time factors can be provided.)

[0093] As is common practice with optical disks in general, the disk ofthe invention may be provided with a table of contents for allowing theuser to select a particular part to play, or simply to inform the userof precisely what is on the disk and how long each part takes to play.Field 27, if included, is a table of contents. If only one version ofthe source material is on the disk, then there is only one table ofcontents. Otherwise, there is an additional field 28 which consists ofthe table of contents for the second version. FIG. 3 sets forth thesub-fields in field 27.

[0094] For lack of a better term, the video presentation is divided upinto what are called “chapters.” For each chapter the table of contentsincludes an 8-bit chapter number, thus allowing a maximum of 255individual chapters. Following each chapter number there is a 20-bitstarting block serial block number. It will be recalled that all of thedata blocks on the disk are numbered serially. In other words, whiledata blocks may be common to both versions A and B, or unique to onlyone of them, the numbers of the data blocks are in serial order alongthe disk track. The table of contents includes the serial block numberof the data block which is the starting block for each chapter.

[0095] Similarly, in order to determine the play time for each chapter,the system must know how many blocks are included in each chapter. Forthis reason, the next piece of information is a 20-bit block duration.Multiplying this number by the block time factor allows the play time ofeach chapter to be determined. Alternatively, the actual running timefor each chapter could be provided instead of the block duration. (Suchinformation could be provided for different versions and standards.)

[0096] In order to display the title of each chapter, language stringsmust be provided. Once again, the system must be advised of thelanguages which are available for displaying chapter titles so that theuser might select one of them. The usual technique of providing a100-bit block for identifying available languages is employed.

[0097] Finally, the actual language strings for identifying individualchapters are provided. Each string ends with an escape character toseparate it from the next string. This is the same technique used inconnection with the “other” audio track definitions discussed above inconnection with field 14.

[0098] Field 29 has a minimum of 100 bits and a maximum of 1200 bits Itwill be recalled that there can be up to 12 authorized standards, i.e.,the final video output can be in up to 12 different formats. In order toinsure conformance with quality standards agreed upon by allmanufacturers of players and all software publishers who have agreed tosupport a common set of specifications, it is possible to preventunauthorized software publishers from publishing disks which will playon players of the invention. Moreover, it is possible to limitparticular publishers to the manufacture of disks which will playaccording to only a sub-set of the 12 standards For example, ifroyalties are to be paid on each disk which is manufactured according tothe agreed-upon specifications, and the royalties vary in accordancewith the number of standards according to which a disk can be played, itis possible to limit certain software manufacturers to only the sub-setof standards for which they have agreed to pay. For this reason, thereis an encrypted authorization code for each standard; the codes are allstored in field 29. The disk will play according to a particularstandard only if the proper encrypted authorization code is contained onthe disk. Field 29 includes 100 bits for each of the standardsauthorized in field 5. Since at least one standard must be authorizedthere are at least 100 bits. The maximum number of bits is 1200 if all12 standards are authorized.

[0099] The encryption scheme is based upon the principles of public-keycryptography. Public-key cryptography is by now well known, and aparticularly clear exposition of the subject is to be found in theAugust 1979 issue of Scientific American, in an article by Hellmanentitled “The Mathematics of Public-Key Cryptography.” The use of apublic-key cryptosystem allows a message to be encrypted at site A inaccordance with a secret key, transmitted to site B, and decrypted atsite B in accordance with a public key. The secret key for encryptingthe message is known only to the transmitter. Such a scheme is typicallyused to authenticate a message. Upon decryption of the transmittedencrypted message at the receiving site, the message will beintelligible only if it was encrypted with the paired private key. Andsince the private key is private, if the decrypted message isintelligible, it must have originated with the owner of the private key.

[0100] Public-key cryptography is used in the invention in the followingway. The actual data on the track is processed by the software publisherin accordance with a predetermined algorithm. The details of theprocessing are not important Any non-trivial processing that provides,for example, a 100-bit result based on the disk data will suffice. The100-bit result is a “message” to be transmitted via the disk in anywherefrom one to twelve encrypted forms. There are 12 cryptosystem key pairs,each associated with a different one of the standards. The private keyfor the first standard authorized on the disk is used to encrypt the100-bit message and the 100-bit encryption is stored in field 29. Thisencryption is the authorization code for the particular standard. Thesame thing is done for all of the other standards authorized for theparticular disk, with the private key associated with each of thesestandards being used in each case.

[0101] The player operating system computes the same 100-bit result ormessage that was originally computed by the software publisher. Theplayer software then uses the public key associated with each of thestandards authorized on the disk to decrypt the respective encryptedauthorization code for that standard. The decrypted message should matchthe message computed by the operating system after processing the diskdata. If they do not match, it is an indication that the softwarepublisher did not have the private key for encrypting the authorizationcode for the particular standard, and the player will not produce avideo signal according to that standard.

[0102] To explain this in another way, let it be assumed that theprivate key for authorized standard N on the disk gives rise to anencrypted message Pri_(N)(X), where X is a message to be encrypted.Similarly, the function Pub_(N)(X) represents the decryption of afunction X using a paired public key. Let it further be assumed that thepredetermined algorithm for processing the data on the disk is known byall player manufacturers and software publishers, and gives rise to a100-bit result which is treated as a “message” M whose content (value)depends on the disk data. For standard N, the software publisher, afterfirst deriving M, stores on the disk the 100-bit encrypted authorizationcode Pri_(N)(M). The player first derives the value M in the same waythat the software publisher did. The player software then uses thepublic key associated with standard N for decrypting the encryptedauthorization code. The operating system thus derivesPub_(N)(Pri_(N)(M)). Since decryption of an encrypted message shouldresult in the original message, the result of this decryption should bethe same value M which the operating system derives by processing thedisk data. If it is, then the particular standard is not onlyauthorized, but the publisher has the right to authorize it. On theother hand, if the decryption of the encrypted authorization code M doesnot match the algorithmic result M derived by the player (because thesoftware publisher did not have the private key with which to derivePri_(N)(M)), then that particular standard is locked out.

[0103] While such a scheme works in the abstract, there is one practicalproblem which must be overcome. Suppose, for example, that the algorithmused to derive the original “message” M involves processing 20 datablocks on the disk with predetermined serial block numbers. (Theprocessing might be something as simple as multiplying by each othersuccessive groups of 100 bits each, and using as the result of eachmultiplication—for the next multiplication—only the 100 leastsignificant bits.) A publisher who is not empowered to authorizestandard N on a disk may nevertheless wish to do so. He does not knowthe private key with which to encrypt the derived value M which isapplicable to his software. Consequently, he does not know what 100-bitencrypted code he should put on the disk which will decrypt in a playerto the value M. But what he can do is copy the 20 predetermined datablocks from some other legitimate disk and put them on his own disk, andalso copy the encrypted authorization code in field 29. Those 20 datablocks, when processed in a player, will result in the value M, and itwill match the “stolen” encrypted authorization code after it isdecrypted in the player. Of course, the software publisher may havecommitted copyright infringement, but that simply compounds the felony.The practical problem which the software publisher faces is that he willhave data blocks which are “played” and which will be totally out ofcontext insofar as his motion picture is concerned. However, because theway that multiple versions of a motion picture can be stored on the samedisk in the first place is that the player can be controlled to skipover the play of certain data blocks, as will be described below, thesoftware publisher can encode his other data blocks so that the copieddata blocks are not played. In this way, the encryption protection canbe rendered ineffective.

[0104] The solution is that while the algorithm that derives the“message” M in the first place may also operate on predetermined datablocks, it should operate on at least the lead-in section of the track.There is no way that an unauthorized publisher can copy the lead-intrack fields from another disk because that would give a playerincorrect information about the video and audio contents on theunauthorized publisher's disk. The lead-in data is a function of theparticular subject matter of the disk, and it must appear in the trackin order for the disk to play properly. Thus the information representedon FIG. 3 can be treated as the “message” M whose encryptions, one foreach authorized standard, are derived using respective private keys andare stored in lead-in field 29. (Strictly speaking, the “message” M isthe result of processing all fields except field 29. Also, the longerfields, such as those containing software, can be omitted from theprocessing.) The player derives the same “message”, decrypts anencrypted authorization code with the public key associated with therespective standard, and then compares the two. If they don't match, theplayer determines that that particular standard has not been authorizedfor the particular disk's publisher.

[0105] The encrypted authorization code field is shown toward the end ofFIG. 3 and thus the corresponding processing is depicted toward the endof the flowchart of FIGS. 5A-5C to be discussed below. The positioningof the encrypted authorization code field as shown facilitates adescription of its processing, but in fact the field may advantageouslybe placed at the start of the processing. It will be recalled thatspecial software may be read from the disk to modify the normal playersequencing. It is therefore conceivable that a counterfeiter could writespecial software which causes the authorization code processing to bebypassed. By doing the processing before any special software is evenread, the processing cannot be bypassed.

[0106] Returning to a description of the lead-in track fields, field 30is a 1-bit data block command/data flag. This bit informs the operatingsystem whether the data blocks include command information or data whichis to be read during play of the disk. How the system determines whethera particular data block contains commands or data will be explainedbelow. Field 30 simply indicates whether there is any such informationat all. Finally, fields 31 and 32 are catch-all fields for allowing thedisk to control unusual ways in which the player processes theinformation on the disk. It will be recalled that field 3 contains aflag which indicates whether field 4 contains special software whichcauses the player to operate in accordance with a program that istotally different from that usually employed, field 12 indicates whetherfield 13 contains special mixing/deletion software for use with the“other” audio tracks, and field 17 contains a flag which indicateswhether field 18 contains special version software for processing the4-bit multiple version code. Field 31 indicates whether there is“supplemental” software in field 32. The supplemental software isdifferent from the special software of field 4 in that the software infield 4 is basically a substitute for the processing which is normallyused, while the supplemental software generally works with that code, inconjunction with commands and data which are to be found in the datablocks.

[0107] Typically, the supplemental software would allow play of a videogame, with related commands and data in the data blocks determining thecourse of play. But there are other uses of this technique. As anotherexample of the way in which supplemental software, and commands and datain the data blocks, can be used, consider a disk designed to play aclassic motion picture with subtitles, but which is also provided with acritical commentary which is to be displayed periodically in lieu ofsubtitles, perhaps during moments when the screen is caused to go blankexcept for the critical commentary. To show the flexibility which ispossible, let us even consider a case where the critical commentary isto be in a different language. What is required in such a case is thatthe subtitle buffer 59 on FIG. 2 be loaded during the play of some datablocks with subtitles in one language and with subtitles in anotherlanguage during play of other data blocks (some data blocks thuscontaining subtitles corresponding to the original motion picture, andothers containing critical commentary in another language). In such acase, the system must somehow be told to switch back and forth betweenlanguage subtitles, i.e., different subtitle tracks have to be processedin different data blocks. This can be conveniently controlled by issuingcommands in the data blocks themselves. Similarly, if it is desired toblank the screen and interrupt the picture during display of commentary,a data block might include a data value which represents the duration ofthe blanking. Alternatively, if a commentary is to be made in adifferent language, it could be a different audio track which isselected for the purpose. In any case, the special software loaded fromfield 32 would control the processing of the commands and data containedin the data blocks, and would work in conjunction with the operatingsystem of the player.

[0108] Processing of the Lead-In Track Fields

[0109] The flowchart of FIGS. 5A-5E depicts the processing of theinformation in the lead-in track fields. A description of thispreliminary processing is presented at this point, with the functions ofthe individual fields in mind. The fields in the data blocks, as well asprocessing of the data blocks, are discussed below.

[0110] The system processing begins, as shown at the top of FIG. 5A,with the reading of default settings. These are settings established byDIP switches, ROM codes, or the use of any other device or techniquewhich configures the system on power-up. It is typical inmicroprocessor-based systems to reset all flags and to read defaultsettings when power is first turned on.

[0111] There are four default settings which are thus determined inorder to configure the system. The first is the standard—players sold inthe United States, for example, will typically be configured, in thedefault state, to produce an NTSC video signal.

[0112] The next default setting is language—the sound track dialoglanguage, the subtitle language (if any), and the language in whichmenus are to be presented on the display. In the United States, forexample, the default language would be English. If the user does notinform the player that a language other than English is desired for oneor more of these functions, audio language track 10 will be used togenerate the sound track, and character strings in the English languagewill be used in setting up the mixing/deletion menu for the “other”audio tracks and for the table of contents. As for subtitles, the usualdefault is “no language.”

[0113] The third default is the aspect ratio, 4:3 in the United States.The aspect ratio determines the relative dimensions of the displayrepresented by the final video output signal.

[0114] Finally, the parental lock status is determined. In the system ofFIG. 2, this simply entails a determination of the setting of lock 81.But it is also possible to dispense with a physical lock and key, and tostore the parental lock status in non-volatile memory after firstinputting on the keyboard a password known only to the persons whoexercise control over the lock function.

[0115] As in, many consumer electronic devices, the keyboard can be usedby the user at any time to interrogate or control the player. Routinecontrol sequences which are standard in the art are not shown in theflowcharts. For example, the keyboard, or an associated remote controldevice, can be used to control the volume, fast forward, a jump to aspecified chapter, etc. The normal processing can be interrupted tocontrol a display by operating a menu key, as is known in the art. Atthe start of the processing of FIG. 5A, there is shown a test fordetermining whether the menu key is operated. The reason for showing aninterrogation of whether the menu key is operated at the start of theprocessing, as opposed to any other time during play of the disk, isthat this is the mechanism by which default settings can be changed. Ifthe menu key is operated when power is first turned on, the systemdisplays a menu. As indicated in the flowchart, the user is given thechoice of changing defaults, viewing the table of contents for the disk,and/or (in case the menu key was operated accidentally) simply returningto the processing without changing anything. As indicated, depending onthe menu selection, the defaults are changed, the entire menu selectionprocess is aborted, or a TOC (table of contents) flag is set to 1. Thisflag will be examined later to determine whether the table of contentsshould be displayed.

[0116] Thus far, no information from the disk has been processed. (Inthis description, references are sometimes made to reading a field andsometimes made to processing a field. It is to be understood that evenwhen it is said that after a certain processing step a field is read,the field may actually have been read earlier but stored in a buffer forlater use. Depending on the context, reading a field means to actuallyread it so that the bits appear on the DATA OUT conductor 25 in FIG. 2,or to do something with the data if it has been read earlier andbuffered.) Referring to FIG. 3, the first information field which isread from the lead-in track section is a 40-bit field representingauthorized territories. Next, a check is made to see whether theterritory in which the player was intended for use is one of thoseauthorized on the disk. The player territory is also a kind of defaultsetting, but it is not grouped with the others because it cannot bechanged by the user. (To allow a purchaser who moves from one territoryto another to use his player, the player territory can be changed by anauthorized technician.) If the player has been designed for use inChina, for example, and China is not one of the territories authorizedon the disk, play of the disk is aborted.

[0117] On the other hand, if the disk has been authorized for play inthe player territory, field 3 is read. This single bit simply tells thesystem whether special software is present As shown in the flowchart, ifit is present then the special software is read from field 4 andexecuted. The processing terminates with the “execute special software”step. This is intended to show that the special software in field 4basically replaces the built-in operating system. Such software will beemployed when a radical change in the overall use of the player isinvolved. (As mentioned above, this is not to say that the specialsoftware may not call BIOS routines and the like from the ROM chipscontaining the operating system.)

[0118] If there is no special software present, the system reads thedefault standard, e.g., it determines that an NTSC standard is to beemployed. If the user has changed the default standard through a menuselection, e.g., to PAL, then PAL is the new default standard. Thesystem then accesses field 5 which authorizes up to 12 standards. Thetest which is performed is to determine whether the default standard(the original, or as changed at the start of the processing) isauthorized. If it is not, a menu is displayed which shows the user theauthorized standards, and he then selects one. After an appropriateselection is made, or if the default standard is authorized, the systemprocesses fields 6 and 7. The reading of field 6 informs the player ofthe available audio languages (up to 16, including M&E and 15languages).

[0119] Once again, a default value is tested against a set of allowedoptions. Earlier, it was the default standard that was tested againstthe authorized standards read from the disk. This time it is the defaultaudio language (either the default language on power-up or a differentlanguage selected by the user if the menu key was operated) that iscompared with all of those available. As shown in the flowchart, if thedefault language is not available, a display is formed which lists theavailable audio languages, and the user selects one of them. The systemthen reads the track types in field 7. This is the field which informsthe operating system whether there is an M&E track, whether it is to beused as a mixing or a switching master, and whether the selectedlanguage track is a complete audio track, is to be mixed with the mixingmaster, or to be switched with the switching master. Next, the trackcodings are read from field 8. Given the selected language, and itstrack type and track coding, as well as information about M&E, mixingand switching, the operating system has all of the information it needsto generate a sound track for the accompanying motion picture whichmeets the needs of the viewer.

[0120] The next thing that is done is to read field 9 to determine thenumber of “other” audio tracks which are on the disk, anywhere from noneup to 63. If there are indeed no “other” audio tracks, all of theprocessing to determine what is to be done with them is bypassed. But ifthere are such tracks, field 10 is first read to determine how they arecoded. Since the user has to be told what is in the tracks before he candetermine what is to be done with them, the system must next determinefrom reading field 11 the “other” track menu languages which are on thedisk. The usual type of check is then made to see whether the menu isavailable in the default language. If it is not, the available languagesare displayed and the user selects one of them.

[0121] As described above, the operating system may execute a standardroutine for reading the menu, displaying it, and interacting with theuser as the user determines what should be done with the “other” audiotracks. But in the event special mixing or deletion is to beaccomplished, special mixing/deletion software is required. Field 12 isread to see whether such software is available and, as indicated in theflowchart, any special mixing/deletion software which is on the disk isread from field 13. Only then are the actual menu items (in the selectedlanguage) read from field 14 and displayed for the user. Using the menusmade available by the operating system, the user selects the play modefor the “other” audio tracks. He can, for example, mix them in anyallowed way, use what is in a track for deletion (by phase inversion)from another more inclusive track, adjust one track for exclusive play,adjust relative audio levels, etc. The special mixing/deletion software,of course, can provide these options as well as others not routinelyoffered

[0122] As shown in FIG. 5B, subtitle information is now processedaccording to the established pattern. First, the system determineswhether subtitles are desired at all. At the very beginning of theprocessing in FIG. 5A, it will be recalled that one of the defaultsettings is the subtitle language. The usual default setting will bethat subtitles are not desired. If that is in fact the case, thesubtitle processing is skipped entirely. But if subtitles are desired,the available subtitle languages are read from field 15. A test is thenmade to see if the default subtitle language is available. If it is not,the available subtitle languages are displayed and the user selects oneof them.

[0123] Next, the 4-bit multiple version code in field 16 is read. Thefirst bit indicates whether there are two versions available, or onlyone. A branch is not made at this point because first the system mustdetermine whether special version software is available, and this isdetermined from field 17. If special version software is available, itis read from field 18 and executed. To the extent that this softwaremust know whether multiple versions are available, and what the codes inthe third and fourth bit positions represent that has already beendetermined. Although indicated in the flowchart that the choicesdisplayed for the user are to select among authorized versions, or toexit, it is to be understood that the display choices will generally bedifferent if special version software is executed. Also, it should beunderstood that there may be special version software even if there isonly one version that can be played. For example, it may be appropriateto warn a viewer that a particular program may be extraordinarilyunsettling, and to ask for a “continue” response before play begins—allof this being separate and apart from an R-rating.

[0124] If special version software is not available, then bits 3 and 4in the 4-bit multiple version code field are used for rating purposes. Atest is performed to see whether the parental lock is on. If it is not,then there are no restrictions on the play of versions A and B, and bothversions are authorized. If it was previously determined that there isonly one version, then that version is considered to be version A and itis authorized.

[0125] On the other band, if the parental lock is on, tests must beperformed to see whether the versions on the disk are R-rated. As shownin FIG. 5C, if version A is R-rated, and so is version B, then play ofthe system is aborted; although not shown, an appropriate message may bedisplayed to advise the user why play has stopped. If version A isR-rated but version B is not, then only version B is authorized. On theother hand, if version A is not R-rated but version B is, only version Ais authorized. Finally, even if the parental lock is on, if neitherversion is R-rated, then both versions are authorized.

[0126] The system next displays the choices available to the user. Hecan choose from among the authorized versions, or he can exit and stopplaying the disk. (This latter case might arise, for example, if a childtries to watch an R-rated version, is told that it cannot be played, anda decision is made to go on to something else more interesting.)

[0127] If there is only one version available, if it is not R-rated, andif there is no special version software, then there may be no need for adisplay—there is only one motion picture which can be played, and thereare no restrictions on who can watch it. Nevertheless, as shown in theflowchart, the user is still given a choice between play of the disk andaborting play. The system could be designed to skip the display in sucha case and simply to assume that the user wants to watch the only motionpicture version which is on the disk. On the other hand, generating thedisplay allows the user to verify that the disk he put in the player isindeed the disk he wants.

[0128] Although the invention has been described thus far in terms ofone or two versions of a motion picture on a disk, it is to beunderstood that there can be three or more versions. This is one of themain reasons for providing the capability of reading special versionsoftware in the first place. This software can include all of theinformation required about the several versions from which menu displaysare formed so that the user can select what is to be played. Asmentioned above, the special version software can allow choices betweenteaching and test modes, and other options having nothing to do withwhether particular motion pictures are adult-rated.

[0129] The system next reads the video availability bit in field 11, andthus determines whether the data blocks which will be processedsubsequently contain video data. If video data is present, then the baseor master aspect ratio in which it has been stored on the disk must bedetermined. The next step thus involves reading field 20 to ascertainwhether the base or master aspect ratio is 16:9 or 4:3. If the masteraspect ratio is 4:3, the next five steps are skipped because pan scanavailability is irrelevant If the default aspect ratio is 4:3, thenthere is a one-to-one correspondence between stored and displayedframes; if the default aspect ratio is 16:9, then a 4:3 frame isdisplayed on a wide screen with a dark band at either side.(Alternatively, the 4:3 image could be expanded to fill the 16:9 screen,with resulting loss of top and/or bottom information.) But if the baseaspect ratio is 16:9, as shown on FIG. 9, there are severalpossibilities which must be explored.

[0130] One of the default values which is determined at the very startof the processing is the aspect ratio. The operating system checkswhether the default aspect ratio is pan scan 4:3. Referring to FIG. 9,if the master aspect ratio is “wide screen” (the flowchart branch beingprocessed), then the possibilities are letter box, pan scan centered onthe wide screen image (not shown in FIG. 9), or pan scan variable (i.e.,with a variable starting column number). If the default is not pan scan4:3, then there are no choices to be made by the user now. The defaultis either wide screen or letter box, and subsequent processing is inaccordance with the default which has already been determined.

[0131] On the other hand, if the default is pan scan 4:3, the issue iswhether variable pan scan information is on the disk. The pan scanavailability bit in field 21 is read. If pan scan is available, it meansthat the data blocks will specify to the operating system the startingcolumn numbers for the pan scan—the user need select nothing at thispoint. On the other hand, if pan scan is not available, and this was theuser's default, he must decide from among two possibilities—a centercut, in which the middle part of every wide screen frame is displayed,or a letter box form in which the entirety of every frame can be seen,but the display has dark bands at the top and bottom. A menu display isformed, and the user selects one of the two modes.

[0132] This use of a common aspect ratio on the disk which neverthelessallows the user to select from many different kinds of displayexemplifies the design approach of the invention. The basic idea is toprovide maximum flexibility while nevertheless storing all of therequired data on an optical disk roughly the size of a conventional CD.Once a wide screen motion picture is stored on the disk, almost noadditional real estate is required to allow the user to generate a videooutput having some other aspect ratio. Although there may be up to 15languages in which dialog can be heard, there are nowhere near 15 fullsound tracks because of the mixing and switching capabilities built intothe player and the manner in which redundant information is eliminatedfrom the audio language tracks. The same thing applies to videostandards. While up to now high-quality video has required a mediumwhich can be played only in NTSC, or PAL, etc., the present inventionallows the same disk to give rise to video signals in up to 12standards. One of the advantages of the invention is that it greatlyreduces the number of different disks that must be produced, forexample, by a motion picture company that distributes its moviesthroughout the world. While it is true that some fields may have to bechanged from time to time, for example, different standards have to beauthorized when videos are released in NTSC and in PAL at differenttimes, such changes are relatively trivial and are easily made.

[0133] Once a decision on the display mode is made, field 22 is read todetermine the total number of data blocks on the disk. If there aremultiple versions, fields 23 and 24 are also read in order to determinethe total number of data blocks in each of the versions. Field 25 isthen read to determine the original frame rate, and field 26 is read todetermine the block time factor.

[0134] Field 27 is then processed. It will be recalled from FIG. 3 thatthis is the field that contains all of the necessary information fordisplay of the table of contents. The table of contents for the selectedversion (field 27 if there is only one version, or there are two and thefirst has been selected; or field 28 if there are two versions and thesecond has been selected) includes a 100-bit representation of theavailable chapter display languages. The default menu language ischecked against those which are available. If the default menu languageis not available, the user is informed of those languages in whichchapter titles can be displayed, and he selects from among them. Once ithas been determined in which language to display chapter information,the various table of contents time durations are calculated. Since it isknown how many blocks are in each chapter, the duration of each chaptercan be determined by multiplying the number of blocks by the block timefactor.

[0135] The table of contents is not necessarily displayed. It isdisplayed only if the TOC flag was set at the start of the processing,the user having indicated that the table of contents should bedisplayed. If the TOC flag is 0, there is no need to display the tableof contents. The system automatically selects the first data block asthe starting point, that is, play of the disk starts at the beginning.On the other hand, if the TOC flag is a 1, the table of contents isdisplayed and the user is given the option of selecting the start point.

[0136] Following the table or tables of contents on the disk are theencrypted authorization codes for the standards authorized in field 5.The operating system reads the encrypted authorization code for thestandard which has been selected. It then reads the predetermined datafor the selected standard. It will be recalled that for each of the 12possible standards, predetermined data on the disk is processed toderive a “message” M which serves as an authorization code. It is thisauthorization code that is stored in encrypted form on the disk usingthe private key associated with each standard. The data which is readfrom the disk may be different for each standard, as long as the samedata is read and processed both during the encryption process and whenthe player derives the “message” M on its own. As discussed above, it ispreferred that the data include at least part of the lead-in fieldsbecause it would be self-defeating for an authorized publisher to copythis data.

[0137] After the predetermined data for the selected standard is read,the authorization code (“message” M) is computed from the data. Usingthe public key associated with the selected standard, which key is builtinto the operating system, the stored authorization code on the disk forthe selected standard is decrypted. The test for whether the softwarepublisher has been authorized to publish disks which will play as videosignals in the selected standard involves comparing the decryptedauthorization code with the computed authorization code. If they do notmatch, play is aborted.

[0138] If the two codes do match, field 30 is read. This single bitsimply informs the master processor whether there are any commands ordata stored in the data blocks other than the normal complement depictedin FIG. 4 to be discussed below. If the flag is a 0, the operatingsystem does not even look for such additional commands or data in thedata blocks. If the flag is a 1, it means that commands or data may bepresent in a data block, but not necessarily so.

[0139] Finally, field 31 is read in order to determine whethersupplemental software is available. If it is, it is read from field 32.The supplemental software, as described above, is not to be used in lieuof the operating system software, but rather as a supplement to it. Thisis the basic difference between the software in fields 4 and 32.Generally speaking, the supplemental software operates on commands anddata included in the data blocks in a field whose presence is indicated(although not necessarily in every data block, as will become apparentbelow) by the supplemental software flag.

[0140] With the reading of field 32 and its integration with theoperating system, the read head in the disk drive is caused to move tothe start point. As described above, the start point is either the firstdata block or a data block determined by the user if a chapter otherthan the first has been selected. Data blocks are read in sequence anddemultiplexer 63 on FIG. 2 distributes the data fields to variousbuffers. As indicated in the flowchart, the reading of a data blocktakes place only if no buffer is full. Furthermore, before a new datablock is read, the system checks whether there are any interrupts whichmust be serviced. Controller 41 is the source of all interrupts. Forexample, if the user has operated the keyboard, the controller generatesan interrupt on line 43 of FIG. 2 which temporarily halts the reading ofdata blocks. After the interrupt has been processed, or if there is nointerrupt which must be serviced, the next data block is read. As willbe described, the serial block number is one of the first things that isread. The block number/pointer analyzer 47 knows the number of the nextblock which is required Very often, this will simply be the next blockin the serial sequence. However, the block number may be out ofsequence, for example, if a jump is to be made to a new chapter, or, aswill become apparent below, certain blocks have to be skipped on a diskwhen playing one of multiple versions of a motion picture. In any event,the systems checks whether the block being read is the correct one. Ifit is not, a branch is made back to the start of the block readingprocess so that a different block can be read. Also, gate 61 on FIG. 2is closed so that the “wrong” data on conductor 2) is not extended todemultiplexer 63.

[0141] If the block read is the required block, one of the first thingsread immediately after the block number is pointer data. The pointerdata is used by block number/pointer analyzer 47 to determine the blocknumber of the next data block that is required, as indicated toward theend of the flowchart. This block number is transmitted over cable 49 tomicroprocessor disk drive controller 27 in order that it access thisdata block at the completion of the reading of the current data block.As indicated at the end of the flowchart, the remainder of the datablock which is being processed at the moment is read and loaded into theseveral buffers, following which another data block may be read.

[0142] The flowchart just reviewed controls the processing of theplayer. What is actually done with the data read from the data blocks isshown in the flowchart of FIG. 6, and this flowchart will be describedafter the fields in a data block, as listed in FIG. 4, are understood.But in order to appreciate the function of the pointer data which isincluded in a data block, FIGS. 7A and 7B will be described first. Thesefigures depict how data blocks associated with individual or bothversions of a motion picture interrelate with each other, and how thesystem is controlled to skip over certain data blocks in order to play aselected version.

[0143] FIGS. 7A and 7B—The Function of the Pointer Data

[0144] In the illustrative embodiment of the invention, there can be twoversions of the same motion picture on a disk. Most of the data blockswill represent video and audio which are common to the two versions.However, there will be other blocks that are unique to one version orthe other. The question is how to control the reading in succession ofthe data blocks that are required for a selected one of the twoversions.

[0145] For purposes of description, the letters A, B and C will be usedto identify respectively data blocks that are unique to version A of themotion picture, data blocks that are unique to version B, and datablocks that are common to both. FIG. 7B illustrates a portion of thetrack with successive data blocks being labelled A, B or C. It will beunderstood that in practice there may be thousands of data blocks insuccession of the same type, with most of the data blocks on the diskbeing of type C. However, to illustrate the way in which the systemjumps over data blocks that are not required, FIG. 7B shows at most twoblocks of the same type in succession.

[0146] There are two sequences shown in FIG. 7B, one at the top forplaying version B, and the other at the bottom for playing version A. Ifit is version B that is selected, and it is assumed that somehow the Bblock on the left is being played, it is apparent that the next two Ablocks must be jumped over in order to go to the fourth block, a Bblock. After this block is played, the next A block must be jumped over.Two common C blocks are then played, after which a jump must be madeover an A block to another C. The next block, a B, is then played,followed by B, C and B blocks. Finally, a jump is made over an A blockto the last block shown in FIG. 7B, a C block.

[0147] If version A is being played, on the other hand, two successive Ablocks are played, there is then a jump over a B block, the next fiveblocks—A, C, C, A, C—are played, there is next a jump over two B blocksto a C block, and finally there is a jump over another B block to an Aand a following C.

[0148] The pattern which emerges is that there are three kinds oftransitions from one block to another. First, there is the play of ablock immediately following play of the preceding block. There are sevenexamples of this shown in FIG. 7B—AA, BB, CC, CA, CB, AC and BC. The twopossibilities which are excluded are AB and BA, since blocks unique tothe two versions will never be played during the same disk playing, muchless one after the other. While there are seven kinds of transitionsfrom block type to block type, there are really just three basicoperations—going from one block of any type to the next block of anytype; a jump from either an A to an A or C, or from a B to a B or C; ora branch from a C block either to an adjacent A or B, or to a B or Asomewhere down the line. Most transitions are of the first type. Thesecond type occurs when an A is followed by a B (which two blocks cannever be played in succession); a jump must be made from the A to eitheranother A or to a C. Similar remarks apply to a B followed by an A. Thethird type occurs at the end of the play of a C block, when there is nolonger any common material to be played and a switch must be made to oneversion or the other; the next block is played if it is part of theversion selected, or some blocks will have to be jumped over if thebranch is to a block in the other version.

[0149]FIG. 7A shows the state diagram which defines how and whentransitions are made from one block to another. As will be describedbelow, every data block includes a two-bit pointer flag, possiblyfollowed by a field which contains a 20-bit pointer. (When a pointer ispresent, it always points to the serial block number of another datablock.) Referring to the code given in FIG. 7A, if the two-bit pointerflag is 00, it is an indication that the processing should continue withthe next block; in this case, there is no need for a pointer. If thetwo-bit pointer flag is a 01 code, it is an indication that a jumpshould be made to a block in the same version some distance away, or toa C block some distance away. In either case, a pointer is necessary.

[0150] The codes 10 and 11 are used when a branch is to be taken from acommon C block. Which code is used depends on whether the next block isan A or B. If the block after the C is an A, code 10 is used and thepointer is to a B or a C further down the line. If the code is 11, itmeans that the next block is a B, and the pointer is to an A or a Cfurther along the track. The operating system knows which version isbeing played. If version A is being played and the current block has a10 pointer flag, it means that the next block, an A, should be playedafter the present one. There is no need for the pointer. The pointer isnecessary in case version B is being played. In this case, since thenext block is an A, it should not be played. The player should jump tothe block identified by the pointer—either another C, or a B unique toversion B being played.

[0151] Similarly, if version A is being played and the current block isa C with code 11 for its pointer flag, it means that the next block is aB. Since version A is being played, the next block should not be playedafter the current one. Instead, a jump is made to the A or C blockidentified by the pointer. On the other hand, if version B is beingplayed, the system simply continues to the next block.

[0152] The legend on FIG. 7A shows whether or not the pointer is usedwhen 10 and 11 pointer flags are found in a C block. The representation10(P) is an indication that the pointer should be used, and arepresentation 10[P] is an indication that the pointer should beignored. It will be recalled that the 10 code is used for a C block whenthe next block is an A. If version A is being played, the pointer is notneeded. That is why a transition from the C block to the succeedingblock, an A, is shown by the symbol 10[P]. On the other hand, if versionB is being played, since the next block is an A it cannot be playedafter the current C. Instead, there must be a jump to the blockidentified by the pointer and thus use of the representation 10(P)—thepointer points to either a B block or another C.

[0153] Similar remarks apply to the representations 11(P) and 11[P]. Inboth cases, it is a C block which is being played and the next block isa B. If version A is being played, the next block should not be playedand thus the symbol 11(P) is required to show a state transition. On theother hand, if version B is being played, it is the succeeding B blockwhich should be played, and thus the symbol 11[P] is appropriate.

[0154] The four codes, as well as the usages (P) and [P], are depictedin FIG. 7B. Referring to the PLAY B transition sequence, the firsttransition shown is 01(P). It will be recalled that the 01 coderepresents a jump from one version to a block of the same version or toa common block, and a pointer is required. The first transition shown is01(P), a jump from a B block to another B block. The next transition onthe PLAY B line is 01(P), a jump from a B to a C. Next is an example ofthe most common transition of all, 00, the orderly play of the nextblock after the current block.

[0155] The fourth transition in the PLAY B line is represented by a10(P) symbol. The 10 code represents a branch from a C block when thenext block is an A, the example illustrated in FIG. 7B. In such a case,as indicated in FIG. 7A, if it is version B which is being played a jumpis made to the block identified by the pointer—in this case, the next C.

[0156] The 11 code is used to identify a branch from a C block when thenext block is a B. If version B is being played, the case underconsideration, the pointer is not necessary because the next block is tobe played. That is why the next code shown is 11[P]. There follow two 00codes that represent obvious transitions to adjacent blocks, followed bya 11[P] code, a branch from a C block to the succeeding block which is aB. Finally, a jump is made from this B block over the next A block to aC block. This requires a 01(P) code—the code used to jump from a blockof either version to a block of the same version or a common block.

[0157] The PLAY A sequence in FIG. 7B assumes that it is version A thatis being played. The first four codes represent transitions to adjacentblocks, or a jump from a block of one version to a block in the sameversion. The next code, 10[P], is used to show a branch from a C blockto an adjacent A block. The pointer is not used since version A is beingplayed, and code 10 is employed because the next block is an A block.The next 00 code symbolizes the transition from the A block to asucceeding C block.

[0158] Next is a jump from a C block to another C block, skipping overtwo B blocks. The 11 code is used because this is the code employed whena B block follows a C block. The symbol used is 11(P), not 11[P],because the pointer is required in going from one C block to a C blockfurther down the line. Similarly, the next code is again a 11(P) code tosymbolize a branch from a C block to an A block further down the line.The sequence in FIG. 7B ends with a transition from an A block to thenext block which is a C, for which the code 00 is used.

[0159] The state diagram of FIG. 7A summarizes all possibilities.Consider first the state in which an A block is being processed,represented by the circle with an A in it at the upper left The two-bitpointer flag in an A block is 00 if the next block is also an A (shownby the transition from A back to A). If the next block is a B, en theother hand, then it clearly should not be played. There must be a jumpfrom the A block over the B, either to another A or to a C. In eithercase, the code is 01(P). The drawing shows both a jump over B (toanother A), and a jump over B to a C. The only other transition from anA block is to the next block if it is a C. This is shown by the code 00.

[0160] There are four similar transitions shown for state B, i e., whena data block in version B is being read. The 00 code is used if the nextblock is a B or a C. The 01(P) code is used when the next block is an A,and it is jumped over so that the system can next read another B or a C.

[0161] Transitions from a C block are more complicated because there areseven of them, rather than only four as for each of the A and B blocks.If the next block is also a C, the code is a simple 00—read the nextblock. If the next block is a B and a jump must be made to another C,the code 10(P) controls the jump over the A. Similarly, the code 11(P)controls a jump over a B to another C. It will be recalled that thesetwo codes are used to control branches from a C block, depending onwhether the next block is an A or B. In either case, if the next blockis not to be read, it (and blocks like it) must be jumped over to thenext C.

[0162] However, after reading a C block, it is also possible to read anA or a B. To read an A, one of the codes 11(P) or 10[P] is used. The 11code is employed when the next block is a B, in which case the pointeris required. The 10 code is used when the next block is an A, in whichcase the pointer is not used. Similarly, to read a B block next, eitherthe code 10(P) or 11[P] is used. The former is employed when the nextblock on the disk is an A, and the pointer is required because thisblock must be jumped over. On the other hand, if the next block is a B,the code 11 tells the system to go on to this next block, and in theprocess to ignore the pointer because it is not needed.

[0163] Perhaps the most important point to recognize is one which is notapparent from the drawings, and that is that most blocks will contain 00pointer flags and no pointers. (The 00 code is the only one without afollowing pointer field.) That is because once a frame of either versionis being played, or once a frame of the common material is being played,it is most likely that the next frame will be of the same type.Consequently, a 00 code alone does the job. The net result is that twoversions of the same motion picture can be stored on the disk, with theuser having the option of playing either (provided that it is allowed bythe parental lock), and only a tiny fraction of the total disk realestate is “wasted” by housekeeping bits that control transitions fromone block to the next block which is to be read after it. Again, this isin line with the underlying design philosophy of providing maximumflexibility and as many options as possible, without unduly wasting bitsin the process.

[0164] It should also be noted that the invention is not limited toplacing just two versions of a motion picture on a disk. It is possibleto use the same technique with three or more versions (although the needfor so many versions is less likely). In such a case, common blockswould require two pointers, not just one. If there are three versions onthe disk, following a C block, the next block might be an A, B or D. Twopointers would be required to point to the two blocks which are to befound further down the line. Obviously, this is just one of the changeswhich would have to be made. The point is that multiple versions can beaccommodated, albeit with an expenditure of more housekeeping bits.Nevertheless, the total number of pointer bits of this type is stillinconsequential compared with the total number of audio/video bits.

[0165] Data Block Fields

[0166]FIG. 4 depicts the fields of a data block, and the format issimilar to that shown for the fields of the lead-in track in FIG. 3.Every data block begins with a sync word. As discussed above, the syncword pattern cannot appear in the data, and thus when it is detected theoperating system knows that a new data block is about to begin.

[0167] The second field is a 20-bit serial block number. All of theblocks on the disk are numbered in serial order. The block number is thefirst thing read because it is used by block number/pointer analyzer 47in FIG. 2. The block number is essential, for example, when jumping fromone block to another. The read head will usually be positioned at apoint near the desired block, but it is highly unlikely that the correctblock will be selected on the first try. This is especially true sincethe number of bits in the data blocks is variable, and the system has noway of knowing how many bits there are in the blocks being skipped. Byreading the block number at the start of the data block, the system canquickly determine whether the head must be repositioned.

[0168] The third field is a two-bit code which represents whether theblock is part of the A version, the B version, or common to both. (Onlythree of the four possible codes are used.) It might be wondered why thesystem would ever have to check on the version of a particular block,since once play of version A or version B begins, the pointers discussedin connection with FIGS. 7A and 7B will always identify a block which iseither common or part of the version being played. The answer has to dowith fast forward and fast reverse operations. Although these have notbeen discussed at length because they are entirely conventionaltechniques, when fast forwarding, for example, the read head may bepositioned more or less arbitrarily. The video should not be shown if itis of the wrong version. It is not possible to determine the version ofa block simply by looking at the block number or the pointer. Neitheridentify the version. It is for this reason that the system must be ableto determine the version of the block when it is first read.

[0169] Fields 4 and 5 contain the two-bit pointer flag and 20-bitpointer which have been explained at length in connection with FIGS. 7Aand 7B.

[0170] Field 6 is a one-bit flag which may or may not be present.Referring to FIG. 3, the video availability flag in field 19 tells theoperating system whether there is any video in the data blocks. Even ifthere is, however, it does not mean that every data block containsvideo. For a system in which there is a single frame represented inevery data block, and data blocks are processed at a fixed rate, therewould be video in every data block, even if it is “minimal” video whichconsists of a code representing a “no change.” But there may be systemsin which a data block may represent more or less than a single frame.For example, it may be that the video information in a data block, ifpresent at all, is always of the same number of bits. Depending upon thecompression, it may be that many frames are represented in a single datablock. In such a case, some of the blocks would be devoid of video bits.Depending upon the coding scheme, employed, the bit in field 6 informsthe operating system whether there is a field 7 at all. If there isvideo, field 7 contains the video information, terminating with a syncword. As mentioned above, the actual coding of the video and audioblocks does not comprise part of the subject invention. Although MPEGschemes are preferred, others can be used.

[0171] Field 8 contains anywhere from no bits up to 16. It will berecalled that field 6 of the lead-in track contains 100 bit positions,but only N of these (where the maximum N is 16) can represent bits ofvalue 1 because there can be at most 16 audio tracks on the disk (ofwhich M&E is considered to be one of them). For each of these N tracks,field 8 informs the operating system whether there is any audio in thepresent data block. There are thus X “1”s, up to a maximum of N. Thefirst bit position of N-bit field 8 corresponds with the first audiolanguage track identified in field 6 of the lead-in track. The secondbit in field 8 of a data block is associated with the second audiolanguage represented in field 6 of the lead-in track, etc. The reasonthat there are only N (maximum=16) bits in field 8 of FIG. 4, ratherthan 100, is that it is known from the lead-in track which are thelanguages that may be present in a data block. There is no reason toprovide 84 or more bit positions in each data block to indicate that thecorresponding languages are not present when it is known from thelead-in track that they are nowhere to be found on the disk. It must beborne in mind that the value X in FIG. 4 does not equal the value N inFIG. 3. The latter represents the total number of audio languagesanywhere on the disk, and its maximum value is 16. The symbol Xrepresents how many of those N are actually represented in the currentdata block.

[0172] Field 9 contains the X audio language blocks. Suppose that thereare 10 audio languages represented on the disk, but only six of them arerepresented in the current data block. In this case, there would be Xbit sequences corresponding to the audio languages, each ending with anescape character. The escape character is used to separate audio blocksfrom each other. If whenever an audio block is present it has a fixedduration, then, since it is known how many audio blocks are present in adata block from the information in field 8, it is not necessary toprovide a sync word at the end of the field. Variable length audioblocks would require a sync word at the end of the field.

[0173] Field 9 in the lead-in track contains a value from 0 to 63 whichrepresents the number of “other” audio tracks. While there may be M such“other” audio tracks, as shown in FIG. 3, it does not mean that each ofthem is represented in the current data block. Field 10 in each datablock contains M bits, one for each of the “other” audio tracks on thedisk. Whether the current data block actually contains bit informationfor any of these M tracks depends on whether the corresponding bitposition in field 10 contains a 1. If there are Y “1”s and Y is lessthan M, it means that not all of the “other” audio tracks arerepresented in the current data block. Field 11 contains Y “other” audiotrack blocks, each ending with an escape character. It will beappreciated that the way the audio tracks and the “other” audio tracksare represented in the data block are comparable.

[0174] Referring back to FIG. 2, it will be recalled that data bits in adata block are distributed to audio buffers, a video buffer, a pan scanbuffer and a subtitle buffer, as well as to master controller 41 overthe COMMAND/DATA line 65. Thus far, the representation of audio blocks,“other” audio blocks and a video block have been considered in theanalysis of the fields of FIG. 4. Before proceeding with therepresentation of the subtitle data, however, it must be understood thatthere is a difference in the way that subtitle information isrepresented, as opposed to all audio and video data. The latter isrepresented on a block-by-block basis, and the buffers are continuouslyreplenished with new audio and video data Subtitles, on the other hand,need not change from frame to frame. In fact, a subtitle will not evenbe perceived if it does not remain on the screen for more than oneframe. Consequently, once subtitle data is represented in buffer 59 ifFIG. 2, it causes a subtitle to be formed on the display and to remainthere until new subtitle information is loaded into the buffer. Toremove a subtitle without introducing a new one, a new subtitleconsisting of a blank field is loaded into the buffer.

[0175] Field 12 in the data block consists of P bits, each correspondingwith a different one of the P subtitle languages identified in field 15of the lead-in track. (It will be recalled that the first position inevery 100-bit field corresponding to languages does not really representa language, but rather M&E, so that there are a maximum of 99 subtitlelanguages.) Any subtitle for which there is an update in the currentdata block has a 1 in its corresponding position in field 12. There canbe up to Z “1”s, where the maximum value of Z is P.

[0176] For each subtitle language for which there is an update in thecurrent data block, the update appears in field 13. There are Z updateblocks, which ending with an escape character. It is important tounderstand that an update block can be a blank field. This is the way inwhich a subtitle is removed when a new subtitle is not yet to take itsplace.

[0177] Field 14 consists of one bit which may or may not be present. Thefield is present only if field 21 in the lead-in track is a 1. In such acase, pan scan information is available in the data blocks. If pan scaninformation is available, each data block must tell the operating systemwhether it actually contains a new starting column for the pan scan.Field 14 is a single bit, a flag, which indicates whether there is a panscan update. If the bit is a 1, field 15 is a 9-bit column number, i.e.,a pan scan update.

[0178] Finally, field 16 is a single bit which may or may not bepresent, depending on the value of field 30 in the lead-in track. Thisone-bit flag in the lead-in track tells the operating system whethersupplemental commands and data may be present in field 17 of a datablock. If the command/data present flag is a 1, the command/data blockis read from field 17. The field ends with an escape character.

[0179] A data block field thus contains up to six different types ofdata—audio, “other” audio, video, pan scan information, subtitles and acommand/data block. These are the six types of information which werediscussed above in connection with FIG. 2, with demultiplexer 63distributing the different blocks of information to the audio buffers,video buffer, pan scan buffer, subtitle buffer and master controller.

[0180] Processing of the Data Block Fields

[0181] The processing of the data in a data block is relativelystraight-forward. The processing shown in the flowchart of FIG. 6dovetails with the data block fields themselves shown in FIG. 4.

[0182] It has already been described how block number/pointer analyzer47 on FIG. 2 processes the serial block number, version, two-bit pointerflag and pointer contained in fields 2-5 of a data block. The next fieldis the video present flag. As shown on FIG. 6, if it is determined thatvideo data is present, video buffer 55 on FIG. 2 is loaded with thevideo in field 7. If video data is not present, the buffer simply has amarker loaded into it.

[0183] It is important to understand the need for markers. In order forthe operating system always to be able to synchronize video, audio,subtitle, etc. information, it must be able to tell where in the severaldifferent buffers is the information from the same data block. In otherwords, the operating system must know which part of the audio data in anaudio buffer goes with which part of video data in the video buffer.Otherwise the various information items cannot be synchronized with eachother. By providing markers in the buffers for data which is not presentin the data blocks, the operating system can keep the various items ofinformation synchronized with each other.

[0184] Next, the operating system looks at field 8 to determine how manyof the N audio tracks on the disk (see FIG. 3) actually are representedin the current data block. The same is true of the M “other” audiotracks represented in field 10. All of the audio and “other” audio trackdata are loaded into their respective buffers. The flowchart shows thesequencing only for the first and last of the audio tracks. In eachcase, a test is performed to see whether the audio track or “other”audio track has data present in the current data block. Each of thetracks results in something being loaded in its respective buffer—eitheractual data followed by a marker, or a marker alone.

[0185] After the video and audio information, a data block containssubtitle updates. If there is update information for the subtitles inthe selected language, it is loaded in the subtitle buffer; otherwise amarker alone is stored. The three blocks pertaining to subtitles pertainonly to a single track, that corresponding to the selected subtitlelanguage.

[0186] Next, the pan scan update flag in field 14 is read. If pan scanupdate information is present, it also gets loaded, this time in a panscan buffer. If no new information is available, a marker is simplyplaced in the pan scan buffer to indicate that another data block hasgone by with no new pan scan update information.

[0187] Finally, the system determines whether there are commands or dataavailable (if the lead-in track field 30 says that commands or data areto be found at all in the data blocks). If command/data is present,i.e., field 16 in the data block is a 1, it is loaded from field 17 intomemory in the master controller 41 of FIG. 2. If there are no commandsor data available only a marker is loaded in the microprocessor memory.

[0188] It should be noted that none of the processing sequences of FIG.6 shows a check being made whether the respective type of information isavailable on the disk in the first place. But it is to be understoodthat a test such as “is command/data present?” really consists of twoparts. First, is the data block command/data flag in field 30 of thelead-in track a 0 or 1? If it is a 0, commands and data are not evenlooked for during the processing of a data block. On the other hand, ifcommand or data may be present in a data block as a result of the dataflag in field 30 of the lead-in track being a 1, then each data blockhas its field 16 checked to see whether the command/data present flag isa 1. It is the value of the flag in the data block field whichdetermines whether only a marker gets loaded, or a marker following databits. Similar remarks apply to the other sequences. For example, thereis no reason to check whether a pan scan update is present if from thelead-in track it is determined that pan scan information is nowherepresent on the disk.

[0189] Although the invention has been described with reference to aparticular embodiment, it is to be understood that this embodiment ismerely illustrative of the application of the principles of theinvention. Numerous modifications may be made therein and otherarrangements may be devised without departing from the spirit and scopeof the invention.

1. A system for controlling play of the audio tracks of a softwarecarrier, said software carrier having recorded thereon (i) an imageprogram, (ii) a plurality of audio tracks synchronized with said imageprogram, and (iii) a code for each of said audio tracks identifying itsuse as either a switching master, a mixing master, a track to beswitched with a switching master, or a track to be mixed with a mixingmaster, comprising: (a) means for playing said software carrier andderiving therefrom said audio track codes, an image signal, and audiotrack signals, (b) means for processing said audio track codes todetermine how said audio track signals should be mixed or switched, and(c) control means for mixing or switching said audio track signals inaccordance with said audio track codes to derive an audio signalsynchronized with said image signal.
 2. A system in accordance withclaim 1 wherein said software carrier has recorded thereon a code foreach of said audio tracks indicative of the language of any dialogtherein, and further including means for selecting an audio track to bemixed or switched in accordance with the dialog language desired by auser.
 3. A system in accordance with claim 2 wherein said control meansswitches or mixes a selected audio track with a switching master or amixing master in accordance with the identifying code associated withthe selected audio track.
 4. A system in accordance with claim 2 whereinany switching master audio track on said software carrier has associatedtherewith a switching master identifying code, and any mixing masteraudio track on said software carrier has associated therewith a mixingmaster identifying code, and further including means for selectingeither a switching master audio track or a mixing master audio track forrespective switching or mixing with the selected audio track inaccordance with the identifying code associated with the selected audiotrack.
 5. A system in accordance with claim 4 wherein on said softwarecarrier at least one switching master audio track or one mixing masteraudio track includes M&E.
 6. A system in accordance with claim 5 whereininformation recorded on said software carrier is recorded in separatelyidentifiable blocks, each software carrier block contains indicia ofwhich audio tracks in the block represent a signal, and said controlmeans operates on only the audio tracks in any block that are requiredto derive an audio signal in accordance with the dialog language desiredby a user and said audio track codes.
 7. A system in accordance withclaim 6 wherein said software carrier has recorded thereon anidentification of the type of each audio track, and further includingmeans for processing derived audio signals in accordance with said tracktype identifications.
 8. A system in accordance with claim 4 whereinsaid software carrier has recorded thereon a representation of theavailable dialog languages on the software carrier, and furtherincluding means for representing a default language, said means forselecting an audio track being operative to select an audio track inaccordance with the default language which is represented and theavailable dialog languages on the software carrier.
 9. A system inaccordance with claim 8 further including means, responsive to saiddefault language matching none of said available languages, for allowingthe user to choose an available language.
 10. A system in accordancewith claim 2 wherein said software carrier has recorded thereon arepresentation of the available dialog languages on the softwarecarrier, and further including means for representing a defaultlanguage, said means for selecting an audio track being operative toselect an audio track in accordance with the default language which isrepresented and the available dialog languages on the software carrier.11. A system in accordance with claim 10 further including means,responsive to said default language matching none of said availablelanguages, for allowing the user to choose an available language.
 12. Asystem in accordance with claim 11 wherein said control means switchesor mixes a selected audio track with a switching master or a mixingmaster in accordance with the identifying code associated with theselected audio track.
 13. A system in accordance with claim 1 furtherincluding means for selecting an audio track, and wherein said controlmeans switches or mixes a selected audio track with a switching masteror a mixing master in accordance with the identifying code associatedwith the selected audio track.
 14. A system in accordance with claim 1wherein any switching master audio track on said software carrier hasassociated therewith a switching master identifying code, and any mixingmaster audio track on said software carrier has associated therewith amixing master identifying code, and further including means forselecting either a switching master audio track or a mixing master audiotrack for respective switching or mixing with the selected audio trackin accordance with the identifying code associated with the selectedaudio track.
 15. A system in accordance with claim 14 wherein on saidsoftware carrier at least one switching master audio track or one mixingmaster audio track includes M&E.
 16. A system in accordance with claim 1wherein on said software carrier at least one switching master audiotrack or one mixing master audio track includes M&E.
 17. A system inaccordance with claim 1 wherein said software carrier has recordedthereon a code for each of said audio tracks indicative of the languageof any dialog therein, information recorded on said software carrier isrecorded in separately identifiable blocks, each software carrier blockcontains indicia of which audio tracks in the block represent a signal,and said control means operates on only the audio tracks in any blockthat are required to derive an audio signal in accordance with thedialog language desired by a user and said audio track codes.
 18. Asystem in accordance with claim 17 wherein said software carrier hasrecorded thereon an identification of the type of each audio track, andfurther including means for processing derived audio signals inaccordance with said track type identifications.
 19. A system inaccordance with claim 1 wherein said software carrier has recordedthereon an identification of the type of each audio track, and furtherincluding means for processing derived audio signals in accordance withsaid track type identifications.
 20. A system for controlling play ofthe audio tracks of a software carrier, said software carrier havingrecorded thereon (i) a plurality of audio tracks, and (ii) a code foreach of said audio tracks identifying its use as either a switchingmaster, or a track to be switched with said switching master,comprising: (a) means for playing said software carrier and derivingtherefrom said audio track codes and audio track signals, (b) means forprocessing said audio track codes to determine how said audio tracksignals should be switched, and (c) control means for switching saidaudio track signals in accordance with said audio track codes to derivean audio signal.
 21. A system in accordance with claim 20 wherein saidsoftware carrier has recorded thereon a code for each of said audiotracks indicative of the language of any dialog therein, and furtherincluding means for selecting an audio track to be switched inaccordance with the dialog language desired by a user.
 22. A system inaccordance with claim 21 wherein on said software carrier said switchingmaster audio track includes M&E.
 23. A system in accordance with claim21 wherein information recorded on said software carrier is recorded inseparately identifiable blocks, each software carrier block containsindicia of which audio tracks in the block represent a signal, and saidcontrol means operates on only the audio tracks in any block that arerequired to derive an audio signal in accordance with the dialoglanguage desired by a user and said audio track codes.
 24. A system inaccordance with claim 20 wherein said software carrier has recordedthereon an identification of the type of each audio track, and furtherincluding means for processing derived audio signals in accordance withsaid track type identifications.
 25. A system in accordance with claim20 wherein said software carrier has recorded thereon a representationof the available dialog languages on the software carrier, and furtherincluding means for representing a default language, and means forselecting an audio track to be switched in accordance with the defaultlanguage which is represented and the available dialog languages on thesoftware carrier.
 26. A system in accordance with claim 25 furtherincluding means, responsive to said default language matching none ofsaid available languages, for allowing the user to choose an availablelanguage.
 27. A system for controlling play of the audio tracks of asoftware carrier, said software carrier having recorded thereon (i) aplurality of synchronized audio tracks, and (ii) a code for each of saidaudio tracks identifying its use as either a mixing master, or a trackto be mixed with said mixing master, comprising: (a) means for playingsaid software carrier and deriving therefrom said audio track codes andaudio track signals, (b) means for processing said audio track codes todetermine how said audio track signals should be mixed, and (c) controlmeans for mixing said audio track signals in accordance with said audiotrack codes to derive an audio signal.
 28. A system in accordance withclaim 27 wherein said software carrier has recorded thereon a code foreach of said audio tracks indicative of the language of any dialogtherein, and further including means for selecting an audio track to bemixed in accordance with the dialog language desired by a user.
 29. Asystem in accordance with claim 28 wherein on said software carrier saidmixing master audio track includes M&E.
 30. A system in accordance withclaim 28 wherein information recorded on said software carrier isrecorded in separately identifiable blocks, each software carrier blockcontains indicia of which audio tracks in the block represent a signal,and said control means operates on only the audio tracks in any blockthat are required to derive an audio signal in accordance with thedialog language desired by a user and said audio track codes.
 31. Asystem in accordance with claim 27 wherein said software carrier hasrecorded thereon an identification of the type of each audio track, andfurther including means for processing derived audio signals inaccordance with said track type identifications.
 32. A system inaccordance with claim 27 wherein said software carrier has recordedthereon a representation of the available dialog languages on thesoftware carrier, and further including means for representing a defaultlanguage, and means for selecting an audio track to be mixed inaccordance with the default language which is represented and theavailable dialog languages on the software carrier.
 33. A system inaccordance with claim 32 further including means, responsive to saiddefault language matching none of said available languages, for allowingthe user to choose an available language.
 34. A method for controllingplay of the audio tracks of a software carrier, said software carrierhaving recorded thereon (i) a plurality of audio tracks, and (ii) a codefor each of said audio tracks identifying its use as either a switchingmaster, or a track to be switched with said switching master, comprisingthe steps of: (a) playing said software carrier and deriving therefromsaid audio track codes and audio track signals, (b) processing saidaudio track codes to determine how said audio track signals should beswitched, and (c) switching said audio track signals in accordance withsaid audio track codes to derive an audio signal.
 35. A method inaccordance with claim 34 wherein said software carrier has recordedthereon a code for each of said audio tracks indicative of the languageof any dialog therein, and further including the steps of selecting anaudio track to be switched in accordance with the dialog languagedesired by a user.
 36. A method in accordance with claim 35 wherein onsaid software carrier said switching master audio track includes M&E.37. A method in accordance with claim 35 wherein information recorded onsaid software carrier is recorded in separately identifiable blocks,each software carrier block contains indicia of which audio tracks inthe block represent a signal, and in step (c) the only audio tracks inany block that are operated upon are those required to derive an audiosignal in accordance with the dialog language desired by a user and saidaudio track codes.
 38. A method in accordance with claim 34 wherein saidsoftware carrier has recorded thereon an identification of the type ofeach audio track, and further including the step of processing derivedaudio signals in accordance with said track type identifications.
 39. Amethod in accordance with claim 34 wherein said software carrier hasrecorded thereon a representation of the available dialog languages onthe software carrier, and further including the steps of representing adefault language, and selecting an audio track to be switched inaccordance with the default language which is represented and theavailable dialog languages on the software carrier.
 40. A method inaccordance with claim 39 further including the step of allowing the userto choose an available language responsive to said default languagematching none of said available languages.
 41. A method for controllingplay of the audio tracks of a software carrier, said software carrierhaving recorded thereon (i) a plurality of synchronized audio tracks,and (ii) a code for each of said audio tracks identifying its use aseither a mixing master, or a track to be mixed with said mixing master,comprising the steps of: (a) playing said software carrier and derivingtherefrom said audio track codes and audio track signals, (b) processingsaid audio track codes to determine how said audio track signals shouldbe mixed, and (c) mixing said audio track signals in accordance withsaid audio track codes to derive an audio signal.
 42. A method inaccordance with claim 41 wherein said software carrier has recordedthereon a code for each of said audio tracks indicative of the languageof any dialog therein, and further including the step of selecting anaudio track to be mixed in accordance with the dialog language desiredby a user.
 43. A method in accordance with claim 42 wherein on saidsoftware carrier said mixing master audio track includes M&E.
 44. Amethod in accordance with claim 42 wherein information recorded on saidsoftware carrier is recorded in separately identifiable blocks, eachsoftware carrier block contains indicia of which audio tracks in theblock represent a signal, and in step (c) the only audio tracks in anyblock that are operated upon are those required to derive an audiosignal in accordance with the dialog language desired by a user and saidaudio track codes.
 45. A method in accordance with claim 41 wherein saidsoftware carrier has recorded thereon an identification of the type ofeach audio track, and further including the step of processing derivedaudio signals in accordance with said track type identifications.
 46. Amethod in accordance with claim 41 wherein said software carrier hasrecorded thereon a representation of the available dialog languages onthe software carrier, and further including the steps of representing adefault language, and selecting an audio track to be mixed in accordancewith the default language which is represented and the available dialoglanguages on the software carrier.
 47. A system in accordance with claim46 further including the step of allowing the user to choose anavailable language responsive to said default language matching none ofsaid available languages.
 48. A software carrier having recorded thereon(a) an image program, (b) a plurality of audio tracks synchronized withsaid image program, and (c) a code for each of said audio tracksidentifying its use as either a switching master, a mixing master, atrack to be switched with a switching master, or a track to be mixedwith a mixing master.
 49. A software carrier in accordance with claim 48having further recorded thereon a code for each of said audio tracksindicative of the language of any dialog therein.
 50. A software carrierin accordance with claim 49 wherein at least one switching master audiotrack or one mixing master audio track includes M&E.
 51. A softwarecarrier in accordance with claim 50 wherein information is recorded inseparately identifiable blocks, and each software carrier block containsindicia of which audio tracks in the block represent a signal.
 52. Asoftware carrier in accordance with claim 51 having further recordedthereon an identification of the type of each audio track.
 53. Asoftware carrier in accordance with claim 52 having further recordedthereon a representation of the available dialog languages.
 54. Asoftware carrier in accordance with claim 49 having further recordedthereon a representation of the available dialog languages.
 55. Asoftware carrier in accordance with claim 48 wherein at least oneswitching master audio track or one mixing master audio track includesM&E.
 56. A software carrier in accordance with claim 48 whereininformation is recorded in separately identifiable blocks, and eachsoftware carrier block contains indicia of which audio tracks in theblock represent a signal.
 57. A software carrier in accordance withclaim 56 having further recorded thereon an identification of the typeof each audio track.
 58. A software carrier in accordance with claim 48having further recorded thereon an identification of the type of eachaudio track.
 59. A software carrier having recorded thereon (a) an imageprogram, (b) a plurality of audio tracks synchronized with said imageprogram, and (c) a code for each of said audio tracks identifying itsuse as either a switching master, or a track to be switched with saidswitching master.
 60. A software carrier in accordance with claim 59having further recorded thereon a code for each of said audio tracksindicative of the language of any dialog therein.
 61. A software carrierin accordance with claim 60 wherein said switching master audio trackincludes M&E.
 62. A software carrier in accordance with claim 61 whereininformation is recorded in separately identifiable blocks, and eachsoftware carrier block contains indicia of which audio tracks in theblock represent a signal.
 63. A software carrier in accordance withclaim 62 having further recorded thereon an identification of the typeof each audio track.
 64. A software carrier in accordance with claim 63having further recorded thereon a representation of the available dialoglanguages.
 65. A software carrier in accordance with claim 60 havingfurther recorded thereon a representation of the available dialoglanguages.
 66. A software carrier in accordance with claim 59 whereinsaid switching master audio track includes M&E.
 67. A software carrierin accordance with claim 59 wherein information is recorded inseparately identifiable blocks, and each software carrier block containsindicia of which audio tracks in the block represent a signal.
 68. Asoftware carrier in accordance with claim 67 having further recordedthereon an identification of the type of each audio track.
 69. Asoftware carrier in accordance with claim 59 having further recordedthereon an identification of the type of each audio track.
 70. Asoftware carrier having recorded thereon (a) an image program, (b) aplurality of audio tracks synchronized with said image pro gram, and (c)a code for each of said audio tracks identifying its use as either amixing master, or a track to be mixed with said mixing master.
 71. Asoftware carrier in accordance with claim 70 having further recordedthereon a code for each of said audio tracks indicative of the languageof any dialog therein.
 72. A software carrier in accordance with claim71 wherein said mixing master audio track includes M&E.
 73. A softwarecarrier in accordance with claim 72 wherein information is recorded inseparately identifiable blocks, and each software carrier block containsindicia of which audio tracks in the block represent a signal.
 74. Asoftware carrier in accordance with claim 73 having further recordedthereon an identification of the type of each audio track.
 75. Asoftware carrier in accordance with claim 74 having further recordedthereon a representation of the available dialog languages.
 76. Asoftware carrier in accordance with claim 71 having further recordedthereon a representation of the available dialog languages.
 77. Asoftware carrier in accordance with claim 70 wherein said mixing masteraudio track includes M&E.